Objective: To investigate the effect of L-arginine (L-Arg) on the arrhythmia induced by ischemia-reperfusion (I-R) of right coronary artery in rabbits.Methods: I-R models were established by occluding and loosening the root of the right coronary artery in rabbits, and 48 heathy adult rabbits were randomly divided into: IRa group (120 min reperfusion after 30 min ischemia), IRb group (120 min reperfusion after 90 min ischemia), IRa+ L-Arg group and IRb+ L-Arg group. The changes of ECG and arrhythmia were recorded and graded. Results: ① During the ischemia period,the longer time of IR was,the higer score of the arrhythmia was.The incidence of atrial-ventricular block (AVB), sinus-atrial block (SAB), even sinus arrest were detected and aggravated gradually. ② During the reperfusion period, AVB incidence declined, some of sinus and atrial arrhythmia was transformed into sinus rhythm gradually. Rrhythmia scores in IRa group were significantly lower than those in IRb group at different phases, IRa + L-Arg group and IRb+ L-Arg group were significantly lower than those in IRa and IRb groups, and IRa+ L-Arg group were significantly lower than those in IRb+ L-Arg group. Conlusions: Supplying appropriate L-arginine is beneficial for inhibiting arrhythmia during I-R ,and the longer the time of ischemia is,the weaker the effect of L-arginine on the arrhythmia present during the period of reperfusion.