Historical Accuracy or Pure Fiction?
I guess I'll throw in my $0.02 (that's in Canadian currency btw ;)) worth in regards to your question.
Doing the research would certainly make it a whole lot easier in creating an immersive setting since all the materials that you need (i.e. geographical features, daily life, language, key historical events, etc.) are a simple internet search away, so there's no need to start from scratch.
On the other hand, being too historically accurate could create rigid boundaries, limiting the way you want to unfold your story. Some plot devices that you may have wanted to put into your story may very well become implausible.
Depending what format your story will be in:
1. plot will affect key historical events, changing their outcomes ("what-if" scenarios) or plot will coincide with key events but not affect outcomes (ex. story that looks at key events through a different perspective) => do the research
2. story will only take place in China as a general setting => no research is required if you have a minimal knowledge of East Asian culture, just keep everything in context. IMO plot development and character development/interaction are more important than historical accuracy
*Phew* I seem to be rambling on and on :lecture:
Anyways, hoped I helped (even if a little) and good luck on writing your story :beerchug: