1. using H1b now work in A company, plan to visit China next month, but if do the h1 transfer to B company now, when enter to US, which h1 should use? old one?
-Use the new h1 transfer approval notice to enter US if you still have a valid old H1 visa. If you do not have a valid h1 visa, use this new h1 approval notice to get the h1 visa.
2. during the vacation time in China, if the new company does the transfer and do not get receipt yet, old h1 ok?
-No unless you will work for the Company A after you enter US.