Objective To explore the effect of QizhiJiangtang Capsule on the insulin resistance (IR)in the diabetic rats,and to clarify the action mechanism.Methods The diabetes rat models were induced by high fat diet combined with STZ injection.The successful models of the rats were randomly divided into diabetes group (DM), ShenqiJiangtang Granule group (SQ)and high (QJH),middle-(QJM),low (QJL)doses of QizhiJiangtang Capsule groups;at the same time control group (NC)was established. The drug concentrations in high, middle and low-doses of QizhiJiangtang Capsules groups were 1.35, 0.68, and 0.34 g · kg-1 respectively;and the concentration of ShenqiJiangtang Granule was 0.27 g·kg-1.After the diabetic model was established successfully, the rats were treated for 8 weeks on the basis of drug dose.Then the levels of fasting blood glucose (FBG),fasting insulin (FINS),insulin resistance index (IRI)and biochemical indexes related to lipid metabolism of the rats were measured using blood glucose detector and automatic biochemistry analyser.The gene expression of insulin receptor substrate-1 (IRS-1),phosphatidyl inositol 3-kinase (PI3K),and glucose transporter 4 (GLUT4)in liver tissue were examined by Real Time PCR.The levels of tumor necrosis factorα(TNF-α)and adiponectin (ADPN)in serum were detected using ELISA.Results Compared with control group,the levels of FBG,FINS and IRI of the rats in diabetes group were significantly increased (P<0.05 or P<0.01 );the serum total cholesterol (TC), triglyceride (TG)and low density lipoprotein (LDL)levels were significantly increased (P<0.05 ), while the serum high-density lipoprotein (HDL)level was significantly decreased (P<0.05);the mRNA expression levels of IRS-1,PI3K and GLUT4 in liver tissue were decreased (P<0.05);the level of serum TNF-αwas increased (P<0.05),but the ADPN level was decreased (P<0.05).Compared with diabetes group,the FBG level and IRI of the rats in QizhiJiangtang Capsule and ShenqiJiangtang Granule groups were significantly decreased (P<0.01);the levels of FINS of the rats middle and high doses of in QizhiJiangtang Capsule groups and ShenqiJiangtang Granule group were significantly decreased (P<0.05);the levels of serum TC,TG and LDL of the rats in middle dose of QizhiJiangtang Capsule group and ShenqiJiangtang Granule group were significantly decreased (P<0.05 or P<0.01),but the HDL level was increased (P<0.05);the mRBA expression lvels of IRS-1,PI3K and GLUT4 inliver tissue were increased (P<0.05);the levels of serum TNF-αof the rats in middle dose of QizhiJiangtang Capsule group and Shenqijiangtang Granule group were significantly decreased (P<0.05),but the serum ADPN levels were increased (P<0.05 ). Conclusion QizhiJiangtang Capsule can significantly improve the IR in the diabetic rats,and the pharmacological mechanisms are related to adapting the blood lipid component and insulin signal transduction pathways.