REply

本人是美国公民，有一个位女友准备旅游签证来美，我想她来美国后等3个月后就给她结婚办绿卡，但她有个未满18岁的孩子在国内，她自己先一个人过来，请问，我帮她办绿卡的时候如何也帮她国内的孩子申请？谢谢
-Your fiancée had better apply for the K-1 visa (her child can apply for K-2 visa) to enter US to marry you and apply for green card.
Another choice is that you go to China to marry her, then she can apply for K-3 visa (her child apply for K-4 visa) or immigration visa to enter US.

Technically though your fiancée can apply for B-2 visa to enter US to marry you and then apply for green card, USCIS may think she may have visa fraud (B-2 visa if for tourist, not for green card) and thus, give her trouble. Also her child may have trouble to get the visa in China due to her mother does not return to China after short visiting US as a tourist.