Abstract： Objective To explore the application value of telmisartan combined with calcium dobesilate in patients with non-dipper hypertension complicated with type 2 diabetes mellitus(T2DM).Methods A total of 260 patients with non-dipper hypertension complicated with T2DM in the endocrinology department of our hospital were selected in this study from January 2021 to December 2022.All the patients were randomly divided into telmisartan group(Tel,n=110)and telmisartan+calcium dobesilate group(Tel+Cal-dob,n=150).The blood pressure level,blood pressure rhythm changes,brachial flow mediated dilatation(FMD),carotid radial pulse wave velocity(crPWV),vasomotor factors[nitric oxide(NO),endothelin-1(ET-1),vascular endothelial growth factor(VEGF)]and the incidence of adverse reactions were compared between the two groups.Results There was no significant difference in general data and biochemical indexes between the two groups(P>0.05).After 3,6 and 12 months of treatment,the FMD and NO were higher,while the dSBP,dDBP,24 hSBP,24 hDBP,nSBP,nDBP,crPWV,ET-1 and VEGF were lower than before treatment in both groups(P<0.05).After 3,6 and 12 months of treatment,the FMD and NO were higher,while dSBP,dDBP,24 hSBP,24 hDBP,nSBP,nDBP,crPWV,ET-1 and VEGF were lower in Tel+Cal-dob group than in Tel group(P<0.05).After 3,6 and 12 months of treatment,the conversion rates of dipper blood pressure were higher in Tel+Cal-dob groupthan in Tel group(P<0.05).There was no significant difference in the incidence of adverse effects between the two groups(P>0.05).Conclusion Telmisartan combined with calcium dobesilate is effective in the treatment of patients with non-dipper hypertension complicated with T2DM.