On the basis of more than 3000 cases of laparoscopic gastrectomy with lymph node dissection for gastric adenocarcinoma, we want to apply the Indocyanine Green Tracer, a cheap, easy to operate and no radiation pollution way, to predict the positive lymph nodes in gastric adenocarcinoma, to guid the scope of laparoscopic lymph node dissection for gastric adenocarcinoma.