急需知美國簽証問題 ??????

you don't have transfer your visa to the new passport, if you request them to do so, then they will cancel your existing one and apply a new one for you, for sure, you have to pay again and go thru all those application process

2. you just need to bring along both passport, the old one which with your US visa and as well as your new passport then that will do

Here’s the answer from the US consulate as well, take a look at Q1
http://hongkong.usconsulate.gov/niv_faq.html