|It's very hard to get accurate data regarding to Chinese strategic nuclear force. You have to take a guess work to estimate what kind of systems they have, let alone numbers. Since Chinese has a very different views from west on deterrence issue, they simply hide all the detail.
So we can only take a guess, based on the public resources:
This liquid fuel type ICBM is the only official confirmed one, first generation Chinese ICBM with single warhead, mega ton level yield, entering into service in middle 80s. Some of them sit in silos(I saw one photo before), some stored in tunnels. China has unique geographic condition, with 70% of land covered by huge rock mountains, so it's natural for them to take that advantage. The 80s offical source confirmed the initial tunnel network was completed in early 80s. Some semi-official source stated that China obtained the fire on warning capability in 1984, with 5 command centers. As for number, I think 20 around ICBMs at the end of 80s is credible, which is disclosed by one high ranking offical in 1990, who escaped to US. Since China's main enemy is Soviet Union before 90s, most of their nuclear arsenals are in middle range.
The information of this type ICBM is circulated for quite a time, but never being confirmed by offical source, and no photos/evidences exist. DF-5A is said upgraded from DF-5 in range, and multiple warhead capability.
This solid fuel mobile type ICBM came into public in 1999, and there are quite a lot photos/evidences about it circulated around. Interesting thing is that China never confirms in public it is an ICBM, only indirect evidence proves it. Sources said this type of ICBM started its deployment from 1996, and completed in 2001.
DF-31 in early development stage, the Chinese text indicats ICBM:
This scanned photo shows DF-31 in launch practice:
DF-31 spotted in the field:
Does this photo captured from Chinese TV show its deployment?
Also there are some DF-31 picutres captured in differenc places:
DF-31 in parade, with labels on the vehicles:
DF-31 spotted in the field, no labels on the vechicle:
claimed to be payload of the DF-31, not sure:
With these photos/evidence we can safely conclude that DF-31 has been in service, it not the Chinese tradition to put weapons not in service into public parade anyway.
There are some information around regarding these two types Chinese ICBMs, but never confirmed by the official like with DF31. DF-31A extends DF-31's range from 8000km to 12,000km. And DF-41 is a heavy type ICBM with a striking range to 14,000.
There are tow pictures released to public, don't know from where. DF-31A, or DF-41? Looks qute similar to ss27.