Objective:To study the risk factors affecting the prognosis of patients with type Ⅰ endometrial cancer.Methods:A total of 279 patients with type Ⅰ endometrial cancer admitted to the First Affiliated Hospital of Southwest Medical University were enrolled from January 2010 to January 2015. The clinical data of all patients were retrospectively analyzed. The Kaplan-Meier method was used to estimate patients′ survival rate. Cox regression risk model was used to analyze the risk factors that might affect the prognosis of patients with endometrial cancer.Results:Of 279 patients with endometrial cancer, postoperative recurrence was observed in 36 patients. The 5-year disease free survival rate was 87.10%(243/279). The 2, 3 and 5-year survival rates were 95.9% (95% CI: 93.6%-98.3%), 94.3% (95% CI: 91.6%-97.2%), and 90.4% (95% CI: 86.6%-94.3%). Univariate analysis showed that obesity ( HR=2.194, 95% CI: 1.031-4.671, P=0.041), myometrial invasion ( HR=2.957, 95% CI: 1.382-6.329, P=0.005), tissue grading (G2: HR=3.271, 95% CI: 1.336-8.010, P=0.010; G3: HR=9.933, 95% CI: 3.565-27.672, P<0.001), tumor size ( HR=8.067, 95% CI: 2.426-26.821, P=0.001), abdominal cytology ( HR=3.293, 95% CI: 1.523-7.121, P=0.002), surgery-pathological staging (Ⅲ stage: HR=28.357, 95% CI: 11.516-69.828, P<0.001), nature of lymph node ( HR=14.629, 95% CI: 5.023-42.606, P<0.001), cervical interstitial infiltration ( HR=3.806, 95% CI: 1.653-8.764, P=0.002), accessory metastasis ( HR=9.101, 95% CI: 3.831-21.622, P<0.001) and lymphovascular space invasion ( HR=5.011, 95% CI: 2.233-11.249, P<0.001) were all correlated with the prognosis of the patients. Multivariate analysis showed that the independent risk factors for the prognosis of endometrial cancer patients were depth of myometrial invasion ( HR=2.503, 95% CI: 1.115-5.616, P=0.026), histological grading (G2: HR=3.143, 95% CI: 1.205-8.198, P=0.019; G3: HR=3.655, 95% CI: 1.151-11.610, P=0.028), surgery-pathological staging (Ⅲ stage: HR=27.701, 95% CI: 9.608-79.869, P<0.001) and lymphovascular space invasion ( HR=3.297, 95% CI: 1.370-7.936, P=0.008). Conclusion:Obesity, myometrial invasion, tissue grading, tumor size, abdominal cytology, surgery-pathological staging, nature of lymph node, cervical interstitial infiltration, adnexal metastasis and lymphovascular space invasion all affect the prognosis of patients. Depth of myometrial invasion, histological grading, surgical-pathological staging and lymphovascular space invasion are independent risk factors for the prognosis of patients with Ⅰ endometrial cancer.