S1 visa for a husband (already in China)

Oksana, yes, it is possible for him to get an S1 type while in China. He can first prepare those documents including passport, the application form, a half-length bareheaded color photo, valid registration form of temporary residence, an invitation letter from you and copies of your passport and residence permit, and your marriage certificate. Next, go to the exit and entry administration of the local PSB to convert the L type to S1 type.

Thank you! And 2 more questions: do we need an original of our marriage certificate, or color scan will be ok? And how long will the process of getting this visa take (his L type ends an the end of December, do we have enough time i mean)?

The original marriage certificate is needed.
It may take 7 working days to convert the L type to S1 type. After that, 30 days are needed to apply for the residence permit. I think time is enough if you apply for it now.