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BACKGROUND The diagnosis of Lynch syndrome-associated endometrial cancer patients is significant for early warning of their relatives. The purpose of this study was to provide diagnostic indicators of Lynch syndrome-associated endometrial cancer by screening the differential clinical and genetic characteristics. METHODS Clinical information and hysterectomy specimens were collected from 377 eligible patients with endometrial cancer. The MLH1 methylation level was detected by an EZ DNA Methylation-Gold Kit. According to the above experimental results, the patients were then divided into sporadic endometrial cancer and suspected Lynch syndrome-associated endometrial cancer groups. A total of 62 samples were randomly selected for whole-exome sequencing. IBM SPSS Statistics 21 was used to compare the clinical data between the sporadic and suspected Lynch syndrome-associated endometrial cancer groups, and the relationship between the specific high-frequency-mutation genes and the clinical data. RESULTS According to the results of MMR immunohistochemistry and MLH1 methylation, the sporadic endometrial cancer group included 361 patients and the suspected Lynch syndrome-associated endometrial cancer group included 16 patients in this study. In the clinical analysis, the average age of the suspected Lynch syndrome-associated endometrial cancer patients was 45.50 ± 11.50 years, which was significantly younger than the 51.17 ± 10.03 years of the sporadic endometrial cancer patients (P = 0.028). The average BMI of the suspected Lynch syndrome-associated endometrial cancer patients was 23.43 kg/m2 (CI: 20, 30), which was lower than the 26.50 kg/m2 of the sporadic endometrial cancer patients (P = 0.028). Combined with the WES data, MASP2, NADK and RNF223 were identified as three specific mutation sites related to age, FIGO stage and histology. CONCLUSIONS Compared with the suspected endometrial cancer patients, the Lynch syndrome-associated endometrial cancer patients were younger and less obese. Mutations in MASP2, NADK and RNF223 might be regarded as genetic endometrial cancer features related to clinical characteristics.