Abstract: Objective：To investigate the risk factors of resection-margin involvement(R1)in radical gastrectomy of gastric cancer patients. Methods：The clinical data of 412 cases of radical gastrectomy performed from Jan.2008 to Nov.2009 in Changhai Hospital were analyzed retrospectively. The potential risk factors of proximal resection margins(PRM)/distal resection margins(DRM)R1 were analyzed by univariate and multivariate Logistic regression analysis. Results:The univariate analysis showed that the risk factors of PRM R1 included tumor size,tumor location, Borrmann type,tumor marker in serum,Operation name,PRM distance,T stage,N stage and TNM stage(P＜0.05), and the risk factors of DRM R1 included DRM distance, T stage and vascular invasion(P＜0.05). The multivariate Logistic regression analysis showed that the risk factors of PRM R1 included N3(RR=2.677)and PRM distance(RR=0.423),and the risk factors of DRM R1 was DRM distance (RR=0.407).There were no effect on the PRM R1 when PRM distance ≥9cm and on the DRM R1 when DRM distance ≥4cm under the analysis of RM distance as intercept point. Conclusion：N3 stage and PRM distance(＜9cm)are independent risk factors of the incidence of PRM R1 and DRM distance(＜4cm)is the only independent risk factors of the incidence of DRM R1.