It's been 4 years since my PhD and now I'm applying for a postdoc in China. The Chinese website mentions that the age limit for applicants is 35 years and the applicants must have received their PhD within the last 3 years.
I heard that Chinese universities are strict with age when it comes to postdoc positions. However, they can be more lax on post-PhD experience.
There are two kinds of post-doctoral fellowships available in China. The more traditional Chinese post-doctoral fellowship offers you a government-recognised certificate at the end of training. The more "Western" style does not. There are additional differences having to do with employment, benefits and such that are too individual to list here. Regardless, both are two year contractual commitments.
In general, the more traditional route is very strict in its requirements. You must meet age and graduation requirements and register through a common government portal. The strictness is due, in part, to closely aligned visa requirements. Thus, even if the institution to which you are applying is willing to allow you to attend four years after your PhD, the visa bureau is likely to decline this application.
The more "Western" style of fellowship is much more fluid because it is, in part, more structured like an employment contract and less a training scheme. In addition, there is no need for the academic institute to issue you a government-recognised training certificate. Under this route, there is more flexibility in entry requirements. However, this route is much, much less popular in China. It may not exist in some fields of research.
Good luck.
Yes, you can. I have just spent 2 years in China as a postdoc. When I got there I was aged 36, and good 6 years since my PhD.
When I finished my postdoc I got an official certificate from the government. All procedures were registered at a portal with the central government. Whilst finishing I was offered yet another 2-year-long postdoctoral position at CAS Beijing for a fair salary, but refused it because my experience there was a mess. I never heard of some age limitation for these positions.
However, I should note that China runs mostly by common practice and institutional rules are confusing if followed/known at all. That means that everyone does things in a certain way, and trying to take different paths typically leads to confusion and renegotiation of terms. In the case of postdocs, relatively few Chinese PhDs take them, and usually a single postdoctoral position straight after "graduating" as a PhD. Thus someone seeking a 2nd/3rd postdoc position as an older PhD may look "awkward" for the administration and thus they may not know how to deal with the situation. A typical situation would be that some enrolling system/paperwork includes the options "( ) 1 ( ) 2 ( ) 3 Years since Graduation" at some point where a local secretary gets stuck and starts claiming "it cannot be done". Usually this is to avoid a discussion and getting into trouble.
My bet is that this is a matter of debating with whoever is directly encharged with the paperwork to find out a "mutually agreeable" solution. Actually my sincere advice would be, do a postdoc elsewhere.
Good luck!
