Objective Through establishing a rat model of atrial fibrillation,to study myocardial angiotensin type Ⅰ (AT1R) and type Ⅱ receptor (AT2R) mRNA expression levels in of the state atrial fibrillation and Artemisia annua extract on its expression.Methods Rat model of atrial fibrillation was established,Artemisia annua extract was used for intervention and captopril was adopted as controls.AT1R,AT2R mRNA and protein expression were observed by PCR and Western-blot technology.Results Compared with the control group (0.36±0.05),myocardial AT1R mRNA expression was significantly increased in the model group (0.84±0.04) (P＜0.05).BothArtemisia annua (0.56±0.03) and captopril (0.53±0.04) could significantly reduce the myocardial AT1R mRNA expression in the atrial fibrillation rats (P＜0.05).Captopril showed obvious AT1R mRNA reduction trend,but there was statistical significance compared with Artemisinic extract (P＞0.05).Artemisinic extract showed no impact on AT2R mRNA expression.Conclusion AT1R was closely related to the incidence of atrial fibrillation.AT1R expression was significantly increased in atrial fibrillation rat.The artemisinic extract can be effectively reduced fibrillation myocardial AT1R expression,which may link with its artemisinic antiarrhythmic mechanism.