Objective Effect of Zhibai Dihuang decoction of type of hyperactivity of fire due to yin deficiency and hyperactivity in type 2 diabetic patients with homeostasis model insulin resistance index（HOMA-IR） and evaluate the effect on insulin resistance. Methods Selected type 2 diabetes belongs to Yin-deficiency and Fire-excess， 100 cases of patients with type， using prospective， randomized， single blind control test method. In the control group（50 cases） was given metformin tablets；treatment group（50 cases）， treated with Zhibai Dihuang decoction， every other day 1 agent， combined with metformin hydrochloride tablets and cycle in the two groups for 2 months. Fasting blood glucose（FPG） and fasting insulin（FIns） were measured before and after treatment in two groups， according to the formula Homa-IR=FIns*FPG/22. 5（which is FIns units of U/ml， FPG units for mmol/L） to calculate the Homa-IR. Results The two groups can reduce the level of HOMA-IR in different degree. The statistical data indicated that the treatment group decreased HOMA-IR than in the control group， that is， in the aspects basic treatment plus metformin+Zhibai Dihuang decoction are better than basic treatment+metformin tablets of improving insulin resistance. Conclusion Zhibai Dihuang decoction can effectively improve Yin-deficiency and Fire-excess type 2 diabetic patients with insulin resistance.