The number of nuclear warheads in China's arsenal is a state secret and is therefore unknown. There are varying estimates of the size of China's arsenal. A 2011 Georgetown University study estimated that China has as many as 3,000 warheads[5] hidden in underground tunnels, whereas China is estimated by the Federation of American Scientists to have an arsenal of about 180 active nuclear weapon warheads and 240 total warheads as of 2009...
https://en.wikipedia.org/wiki/China_and_weapons_of_mass_destruction
Both estimates are dated.