Abstract: Objective: To explore the characteristics of spiral CT of lymph nodes metastases in gastric cancer,and provide the evidence for formulating clinical treatment schedule and analyzing the prognosis.Methods: Forty-eight patients with advanced gastric cancer before operation were detected by plain and tri-phasic enhanced spiral CT scan.The potential lymph node metastasis was evaluated by the long diameter,ratio of short to long diameter,density and enhanced degree of lymph nodes,which was compared with the postoperative pathological findings.Results: A long diameter more than or equal to 8 mm,ratio of short-to-long diameter more than or equal to 0.7,CT value more than or equal to 25 HU and enhanced degree more than or equal to 75 Hu of lymph nodes could be as the CT diagnostic standard of lymph node metastasis,which was in consistency with the postoperative pathological findings.Conclusions: The long diameter,ratio of short to long diameter,density and enhanced degree of lymph nodes in tri-phasic enhanced spiral CT scan can diagnose the lymph node metastasis of gastric cancer before operation,which has important value in selecting surgical method and analyzing prognosis.