Objective: The aim of this study is to develop the effective therapy on Dingxin capsule for D-dimer(D-D)of atrial fibrillation. To reveal the mechanism of Chinese medicine with the effects of nourishing Qi and Yin and activating blood in the prevention and treatment of Atrial Fibrillation(AF). Method :Forty rats were randomized to 4 groups:normal group

model group

Dingxin capsule curatio group

verpamil intervention group. The level of D-D of AF rats were measured. Result: With the comparison of treating group and model group

the level of D-D in treating group lowed obviously(P<0.05). Both of them had statistic significance.Both Dingxin capsule group and Verpamil intervention group could low the level of D-D

but Dingxin capsule group is better. Conclusion: Dingxin capsule could correct the level of D-D in AF rats. D-D played important role in the pathogenesis of AF.