Do you mean the green card expired during travel in China? If yes, need to get the transportation letter from any one of the US Consulates in China, not apply for SB-1 visa. It is very simple process. The transportation letter allows you to board the airplane to leave China and enter US. Then, you can file I-90 to renew your green card in US.
-Read this link (You also can find the procedure for Transportation letter in the websites of any one of the US Consulates in China):
http://photos.state.gov/libraries/shanghai/228904/ACS/TLApplicationFormat.pdf
