回来应该不用.

刚查查到的
https://help.cbp.gov/cgi-bin/customs.cfg/php/enduser/std_adp.php?p_faqid=74&p_created=1043364936&p_sid=zuj4zYFj&p_accessibility=0&p_redirect=&p_lva=572&p_sp=cF9zcmNoPTEmcF9zb3J0X2J5PSZwX2dyaWRzb3J0PSZwX3Jvd19*****nQ9MjExLDIxMSZwX3Byb2RzPTAmcF9jYXRzPTAmcF9wdj0mcF9jdj0mcF9zZWFyY2hfdHlwZT1hbnN3ZXJzLnNlYXJjaF9ubCZwX3BhZ2U9MSZwX3NlYXJjaF90ZXh0PXBlcm1hbmVudCByZXNpZGVudHM*&p_li=&p_topview=1

"Lawful Permanent Residents (Green card holder's) do NOT need a passport to enter the United States, however you may need a passport to enter another country. Please contact the embassy of the foreign country you will be traveling to for their requirements."

现在问题是进加拿大要不要, 这个不是十分明确
http://www.cbsa.gc.ca/security-securite/admiss-eng.html

所有跟帖： 

• 进出都看，别查了 -Susan-FF- ♀ (0 bytes) () 08/21/2009 postreply 18:02:49

• 回来了, 一切顺利, 不需要护照. -X-RAY- ♂ (3 bytes) () 08/31/2009 postreply 10:50:00