This is a prospective, randomized, multi-center, controlled clinical trial, aimed to evaluate efficacy and tolerability of thalidomide and CPT-11 in advanced gastric cancer. A total of 900 patients are planned to be enrolled into the study. Patients with diagnosis of advanced gastric cancer will be randomized into two groups, and be treated with thalidomide+ CPT-11 or CPT-11, respectively. The primary end point is time to progression (TTP), and the secondary end points include efficacy, overall survival (OS) and the occurrence of delayed diarrhea.