1. 1.1 apply for OPT now. but not sure if you could get it by Dec. 1.2 If your opt is approved, your F1 visa is still valid, and then apply for H1B when you are back to US in Jan. but... not sure the opt could be approved even it's premium. 2. if you can't get your opt approved by Dec.... apply for premium H1B and get it approved before you leave in Dec. Apply for h1b visa while you are in China.