Abstract：Objective：To study the effects of Shenlian Fumai Granules on electrocardiogram changes， inflammatory response，and oxidative stress related indicators in rats with atrial fibrillation (AF). Methods： SD rats were injected with acetylcholine- calcium chloride (Ach- CaCl2) through tail vein to establish AF model. The model rats were randomly divided into model group， Verapamil group， and Shenlian Fumai Granules group (low- ， medium- ， and high-dose groups). SD rats were used as normal control. After 4 consecutive weeks of treatment in each group，electrocardiograms were recorded using a multi-channel physiological recorder. Detection of serum levels of tumor necrosis factor-α (TNF-α），interleukin-6 (IL-6) and inducible nitric oxide synthase (iNOS) using enzyme- linked immunosorbent assay (ELISA). Results： Compared with the normal group，the duration of AF in the model group rats was prolonged (P＜0.05)，and the levels of serum TNF- α，IL- 6 and iNOS levels were significantly increased (P＜0.05). Compared with the model group ， the medium-dose and high-dose groups of Shenlian Fumai Granules significantly shortened the electrocardiogram PR interval and duration of AF (P＜0.05)，and the levels of serum TNF-α， IL- 6 and iNOS were significantly reduced (P＜0.05). Conclusion： The Chinese medicine Shenlian Fumai Granules can improve the inflammatory response and oxidative stress levels in Ach- CaCl2 induced AF models in rats，and play a potential role in inhibiting the process of AF.