Objective To investigate the relationship between the expressions of mismatch repair （MMR） genes （include hMLH1 and hMSH2） and clinicopathological features and prognosis of hereditary nonpolyposis colorectal cancer （HNPCC）. Methods Immunohistochemistry method （Elivision-two step） was used to test expressions of hMLH1 and hMSH2 proteins （both hMLH1 and hMSH2 protein-positive delimited as MMR protein-positive） in 48 patients with HNPCCaccording to revised Bethesda guidelines， and analyzed the relationship between the expression of MMR protein and clinicopathological features and prognosis of HNPCC. Results Loss rate of hMLH1 protein （20.83%，10/48） was signi-ficantly higher than that of hMSH2 protein （8.33%，4/48）， Ρ＜0.05， and positive expression rate of MMR protein was 70.83% （34/48）. Expression of MMR protein was related with tumor infiltration depth （Ρ＜0.05）. Survival rate of patients with expression and without expression of MMR protein was 85.29% （29/34） and 85.71% （12/14）， respectively， the survival curves of them didn’t significantly differed from each other （Ρ＞0.05）. Conclusions Loss rate of hMLH1 protein is higher than that of hMSH2 protein. Expre ssions of hMLH1 and hMSH2 protein are related with tumor infiltration depth， but not related with prognosis.