As part of the current reorganization of the Chinese military the Second Artillery Corps, which consists largely of short range ballistic missiles plus fewer than a hundred longer range (strategic) missiles, is being upgraded to the new Rocket Force. That means this organization goes from being part of the army to being a fourth branch of the military (along with the army, navy and air force). Because the Rocket Force controls China’s nuclear weapons it has the most firepower of any branch but the fewest personnel. This combining ballistic missiles under one organization is similar to what the Russians did throughout the Cold War. The Russians, like the Chinese now, made their nuclear missile force a brach of the armed forces.
The Rocket Force is spread over most of China, has about 100,000 personnel and is organized into six “Missile Divisions” which have between them over 30 missile brigades. The most common ballistic missile is the DF-21 and the ten DF-21 brigades each have up to six missile battalions (with two mobile launchers each), two maintenance and repair battalions, a site management battalion, a signal battalion and an electronic countermeasures (ECM) battalion. The basic DF-21 is a 15 ton, two stage, solid fuel missile that is 10.7 meters (35 feet) long and 140cm (4.6 feet) in diameter. Range varies (from 1,700-3,000 kilometers) depending on model. These missiles are carried and launched in TELs (transporter erector launcher vehicles). The Second Artillery Corps also controls most of China’s nuclear weapons, although many of the smaller ballistic missiles also have non-nuclear warheads available.
The Rocket Force also controls the new ballistic missiles for nuclear submarines. In 2014 China revealed (apparently by accident) the existence of the DF-26 IRBM (Intermediate Range Ballistic Missile.) This one appears to have a range of 3,500 kilometers and based on the earlier DF-21. There have been reports of such a missile since 2007 and the DF-26C appears to have been in service for several years. The DF-26C is notable because it has the range to hit American military bases on the Central Pacific island of Guam.
China tends to keep a lot of military data secret, even after foreigners have discovered the new items via satellite photos or curious Chinese taking cell phone photos and posting them. That was how the existence of the DF-41 missile became known in the last few years. In 2012 China tested the DF-41 ICBM equipped with a final stage containing multiple warheads. The U.S. announced the test and had apparently monitored it with satellites and other air, land, and sea based sensors. It was not revealed how many warheads were involved, although it was earlier mentioned that China could put 3-10 warheads in the DF-41 final stage. The DF-41 has not been displayed publicly but thanks to cell phone there are photos of the DF-41 available. The DF-41 appears to have had a lot of development problems because few have been built and fewer (less than a dozen) put into service. The DF-41 is the only Chinese ICBM that can reach all of the United States.
China is believed to have over 400 nuclear warheads. Only a few dozen of these missiles can reach the United States. These include the older (and about to be retired) DF-5, plus the newer DF-31A and DF-41. About two thirds of Chinese nuclear warheads are believed to be in missile warheads, most of them DF-21s and these will be replaced by DF-26Cs. Normally the nuclear warheads are stored separately and mated to the missiles only for actual use or the occasional training exercise. In 2009 China announced that its nuclear armed ballistic missiles were not aimed at anyone. Like most countries, China has long refused to say who its nuclear armed missiles are aimed at. Most of those missiles only have enough range to hit Russia or India, or other nearby nations. For a long time most were very definitely aimed at Russia, which had rocky relations with China from the 1960s to the 1990s. But after the Soviet Union dissolved in 1991, the new and much smaller Russia became friendlier with the wealthier (more capitalist but still run by communists) China. Relations between China and India also warmed up, then went into a deep freeze during the past decade.
Since the 1990s China has had about two dozen DF-5 ICBMs nominally in service because they can reach the United States. Few of these are believed to be operational because of reliability and maintenance problems. The U.S. has since installed 18 ICBM interceptor missile systems in Alaska. These are to deal with North Korean missiles but could also destroy most Chinese missiles headed for the western United States. Thus it makes sense for China to simply say that it is not aiming any of its missiles at anyone. Modern guidance systems can be quickly (in less than an hour) programmed for a new target, so it doesn't really matter that, normally, the missiles have no target information in them. The DF-5s, moreover, are liquid fueled and the considerable activity required to ready them for launch can be detected by spy satellites.
The DF-5s are being replaced by the solid fuel DF-41s, which can be moved, erected, and launched from a special truck. With a 15,000 kilometer range they can reach all of the United States. The third stage multiple warheads each with an explosive yield of at least 100 KT. The DF-41s appear similar to the American 36 ton Minuteman III (a 1960s design that has been much upgraded since then).
India is of growing concern to China but there are shorter range ballistic missiles, like the DF-21, to deal with that threat. The Chinese introduced the DF-21 in 1999, and now has over a hundred in service. Many have non-nuclear warheads. This missile has a range of over 1,800 kilometers and can haul a 300 kiloton nuclear warhead. It's a two stage, 15 ton, solid fuel rocket. Launched from Tibet, the DF-21 can reach most major targets in India.
In the early 1990s China put the larger DF-31 into service, sort of. This was China's first solid fuel ICBM (and had a range of over 8,000 kilometers) and roughly equivalent to the U.S. 30 ton Minuteman I (entered service in 1962 with a range of 9,900 kilometers). The DF-31 weighs about 41 tons and is 20 meters (62 feet) long and 2.25 meters (7 feet) in diameter. It was designed for use on submarines, land silos, and mobile launchers (which would halt at those "parking lots in the middle of nowhere" visible in satellite pictures of Qinghai province). The DF-31 has been shown stored in a TEL (transporter, erector, launcher) vehicle. Driving these vehicles along special highways in remote areas provides more protection from counterattacks than using a reinforced silo. Later, the improved DF-31A appeared, with multiple warheads and more range (up to 12,000 kilometers, which could cover most of the United States).
The DF-31 was in development for over twenty years and only had its first successful launch in 2000. It's now believed to have a reliable and accurate guidance system, as well as a third stage that carries three 50 kiloton warheads. Only about a dozen DF-31s are in service, plus about a dozen DF-31As. Many of these appear to be aimed at European Russia.
Then there is a submarine launched missile the JL (Julang) 2 SLBM (Sea Launched Ballistic Missile). This missile has had a lot of problems as have the SSBNs (ballistic missile carrying nuclear subs) that carried them. The 42 ton JL-2 has a range of 8,000 kilometers and would enable China to aim missiles at any target in the United States from a 094 class SSBN cruising off Hawaii or Alaska. Each 094 boat can carry twelve of these missiles, which are naval versions of the existing land based 42 ton DF-31 ICBM. The JL-2 was supposed to have entered service in 2009 but kept failing test launches. No Chinese SSBN has ever gone on a combat cruise because these boats have been very unreliable.