Thanks 863211 for your answers. I have more questions:
1. My H1B (and I-94) is expired the same day last week, can I transfer H1B to a new company in USA (without a valid visa date) or I have to back to China to apply a new H1B?
2. If I transfer in USA and get approved without a valid I-94, and I have to go outside a H1B. And I have to pay twice for this visa, right?
3. Can I make an appointment for H1B in China, and transfer H1B in USA at the same time?While the transfer is pending and I am in USA, am I illegal during this peroid of time?
4. What else I need to do if I need to go back China for H1B rather than transfer in US?
5. What is your suggestion? Transfer in USA or apply in China.
Thanks a lot!