Objective To investigate the clinical risk factors ot endoscopic mucosal resection (EMR) for early colorectal cancer.Methods The clinical data of 140 patients with early colorectal cancer who received EMR at the Changzheng Hospital of Second Military Medical University from January 2005 to June 2012 were retrospectively analyzed.EMR was applied for patients with early colorectal cancer with diameter lesser than 20 mm (protrusive lesions) or 5 mm (depressed lesions).If the diameter of the early colorectal cancer was above 3 cm and can not be resected at one time,endoscopic piecemeal mucosal resection was adopted.Clinicopathological factors including gender,age,tumor location,number,diameter,shape,resection type,depth of tumor invasion,tissue differentiation,lymphatic or vascular invasion,excision degree and curability were retrospectively analyzed.All the patients were divided into the complete cure group and the incomplete cure group.Univariate and multivariate analysis were done using the chi-square test and Logistic regression model,respectively.Results Of the 143 lesions,en-bloc resection was done in 125 lesions,and piecemeal resection in 18 lesions.There were 90 intramucosal carcinomas and 53 submucosal carcinomas.The numbers of high,moderate and low differentiated colorectal cancer were 96,37 and 10.Lymphatic or vascular invasion was found in 8 lesions.The numbers of R0,R1,R2 and Rx resection were 118,15,8 and 2.Two patients with Rx resection were excluded from this study.There were 98 patients (101 lesions) in the complete cure group,and 40 patients (40 lesions) in the incomplete cure group.The results of univariate analysis showed that tumor location,shape and resection type were the risk factors influencing the efficacy of EMR for early colorectal cancer (x2=7.523,16.280,4.156,P ＜0.05).The results of multivariate analysis showed that tumor located at the proximal colon,superficial protrusive and depressed type and piecemeal resection were the independently risk factors influencing the efficacy of EMR (OR =7.219,6.115,5.211,P ＜0.05).Conclusions EMR is not easy to achieve complete cure for early colorectal cancer with superficial protrusive and depressed type or located at the proximal colon.Endoscopic piecemeal mucosal resection should try to avoid.