If you leave US before the H1 transfer is approved, you have to stay in China and ask your employer to send you the h1 transfer approval notice to apply for the H1 visa to come back. You may use premium processing to get the h1 transfer approved within 15 days before you leave if necessary.
能不能用舊公司的I-797回去還是拿新公司的OFFER信和TRANSFER收據也可以辦簽證？
-No.
