Abstract: Four tumor markers CEA,CA199,CA724 and MGAg are chosen in diagnosis of gastric cancer and 228 cases are detected with single or combined methods in all. The results indicate that the positive rates of single detection are all above 70% and that of MGAg is the highest(90.4%). Combined detections of two tumor markers, as judged by double positivity, the positive rate of MG+CA724 is the highest (70.6%), next is MG+CA199(64.6%). It is suggested that MGAg is the first choice in single detection, MG+CA724 group is the first choice in double combined detections and different tumor markers could be chosen according to historogic type in followup patients.