Objective To observe the effect and mechanism of Tangzhiping Granules（TZPG） for diabetic rats with insulin resistance（IR）.Methods Eight rats among ninety Wistar rats of specific-pathogen free（SPF） grade were selected randomly as the normal control group and 82 diabetic rat models with IR were induced by a high fat

high sugar diet and injection of streptozotocin（STZ）.Thirty-two successful modeling rats were randomized into the model group

Tangmaikang Granules（TMKG） group

high-dose TZPG group

low-dose TZPG group

with 8 in each.The same volume of saline was given to the normal control group and model group respectively.The other groups were given intragastric administration of 1.35 g/kg TMKG

2.7 g/kg TZPG and 1.35 g/kg TZPG once daily for 4 weeks respectively.The body weight

blood glucose（BG）

serum insulin（INS）

insulin-like growth factor-1（IGF-1） and endothelin（ET） were detected and the insulin sensitivity index（ISI） was calculated.Results Comparing with the model group

BG

INS and ET were significantly decreased

but ISI and IGF-1 were significantly increased in the TMKG group

high-dose TZPG group and low-dose TZPG group（P<0.05 or P<0.01）.Conclusion TZPG can reduce the body weight

BG

INS and ET

increase ISI and IGF-1 and improve the IR in diabetic rats.