The DF-31 (Dong Feng [East Wind]-31 / CSS-10) is a Chinese intercontinental ballistic missile (ICBM). The three-stage, solid-fueled missile has an estimated range of 7,000 – 11,700 km. China first deployed the DF-31 in 2006, and has developed two successive variants: the DF-31A and DF-31AG.

DF-31 development and specifications

China’s state-owned Academy of Launch Vehicle Technology (CALT) began research and development on a three-stage, solid-fueled ballistic missile August 1970. After successfully test-firing a 2m-diameter solid-propellant motor in late 1983, CALT began development of the DF-31 and its submarine-launched variant, the JL-2, in January 1985. ¹ China first publicly displayed the DF-31 on military parade in 1999.² While initially planned for deployment in the mid-late 1990s, delays in procuring the missile’s guidance system pushed back its service introduction to 2006.³

The original DF-31 (CSS-10 Mod 1) is a three-stage, solid-propellant missile with a range of 7,000 – 8,000+ km.⁴ The missile is approximately 15 m long, 2 m in diameter, and weighs 42,000 kg at launch. It is carried on an 8-axle, tractor-trailer-based launcher built by Hanyang and is launched from its canister with a cold-gas ejection system.⁵ The DF-31 is armed with a single nuclear warhead weighing roughly 1,050 – 1,750 kg. Reports have suggested that the missile possesses an accuracy of 150 – 300 m circular error probable (CEP).⁶ As of 2020, the People’s Liberation Army Rocket Force (PLARF) is known to maintain one DF-31 brigade, totaling six launchers, in Shaanxi Province.⁷

DF-31A

In 2007, the Chinese People’s Liberation Army introduced an an improved version of the DF-31 called the DF-31A (CSS-10 Mod 2). First tested in 1999, the DF-31A incorporates lightened guidance and other unspecified improvements to extend its range past 11,000 km.⁸ The missile is approximately 14 m long and 2 m in diameter. Unlike the DF-31, the missile conceals its warhead beneath a shroud and reportedly employs penetration aids—devices to penetrate missile defenses. These include at least eight decoy warheads.⁹ As of 2020, the PLARF reportedly maintains three DF-31A brigades, totaling 36 launchers, in Qinghai, Yunnan, and Henan Provinces.¹⁰

DF-31AG

In 2017, China publicly displayed the DF-31AG, a variant of the DF-31A with an upgraded launcher and lower support requirements.¹¹ Developed by the China Aerospace Science Corporation (CASC) and the Tai’an Special Vehicle Company, the DF-31AG’s wheeled TEL can traverse unpaved terrain.¹² This off-road capability would allow the DF-31AG to disperse to a wider variety of concealed positions, reducing its vulnerability to counterforce attack.¹³ This configuration also requires fewer support vehicles to operate, allowing for increased readiness. As of 2020, the PLARF is known to maintain 3 DF-31AG brigades, totaling 36 launchers, in Lanzhou, Hunan, and Henan Provinces.