objective:to study the relationship of protection of telomeres 1(pot1) mrna expression,telomerase activity in lymphocytes with the development of type 2 diabetic mellitus(t2dm). methods:one hundred and sixty-two cases with t2dm were test group,162 cases of healthy were control group,real-time quantitative pcr was used to analysis pot1 mrna expression,semi-quantitative trap-elisa was used to analysis telomerase activity. results:the expression of pot1 mrna and telomerase relatively activity in test group were obviously higher than those in control group(p < 0.01). meanwhile,the pot1 mrna expression and telomerase activity were significantly higher in t2dm patients with passable or poor controlled blood glucose compared with controls(p < 0.01),and they were also significantly higher in t2dm patients with different stage of diabetic retinopathy compared with controls(p < 0.01),significant differences also existed among the patients whose time course of t2dm between 5 to 10 years or above 10 years and time course of t2dm less than 5 years or controls(p < 0.01). conclusion:pot1 mrna expression and the telomerase activity were significantly increased with the progression of t2dm;they might be the important evidences in disease prognosis.