OBJECTIVE： To observe clinical efficacy and safety of Tianqi jiangtang capsules combined with metformin in the treatment of elderly patients with type 2 diabetes mellitus complicated with cerebral microvascular lesions. METHODS： A total of 96 elderly patients with type 2 diabetes mellitus complicated with cerebral microvascular lesions were randomly divided into control group （48 cases） and observation group （48 cases）. Control group was given Metformin hydrochloride tablets 0.5 g orally， 3 times a day. Observation group was additionally given Tianqi jiangtang capsules 1.6 g orally， 3 times a day， on the basis of control group. Both groups received treatment for 4 weeks. Clinical efficacies of 2 groups were observed as well as total score of TCM symptoms， the levels of blood glucose （FPG， 2 hPG， HbA1c）， blood lipid （TC， TG， HDL-C， LDL-C），hs-CRP， ET-1， blood rheology and oxidative stress indexes （MDA， SOD）， the occurrence of ADR. RESULTS： The total response rate of observation group was significantly higher than that of control group（89.58％ vs. 70.83％）， with statistical significance （P＜0.05）. After treatment， total score of TCM symptoms， the levels of blood glucose， hs-CRP， ET-1， TC， TG， LDL-C， blood rheology indexes and MDA in 2 groups were significantly lower than before； total score of TCM symptoms， the levels of FPG， 2 hPG， hs-CRP， ET-1， TC， TG， LDL-C， blood rheology indexes and MDA in observation group were significantly lower than control group； the level of SOD in 2 groups were significantly higher than before， and the observation group was significantly higher than control group， and the level of HDL-C in observation group was significantly higher than before treatment and control group， with statistical significance （P＜0.05）. No obvious ADR was found in 2 groups during treatment. CONCLUSIONS： Tianqi jiangtang capsules combined with metformin show significant therapeutic efficacy in the treatment of elderly patients with type 2 diabetes mellitus， and can reduce the levels of blood glucose and lipid， improve blood rheology and oxidative stress reaction， with goud safety.