〔Abstract〕 Objective To observe the effect of amiodarone on L-type calcium channel current in rats single atrial myocytes damaged by H2O2and investigate the effect of amiodarone on electrophysiological characteristics of atrial myocytes. Methods The myocytes were isolated from rats atrial tissues by Langendorff perfusion apparatus,which were randomly divided into three groups: the control group(no treatment),the H2O2group(cells cultured with 100 μmol/L H2O2for 0.5 hour),the amiodarone group(cells cultured with 100 μmol/L H2O2for 0.5 hour and then cultured with amiodarone for 0.5 hour). Whole cell patch clamp technique was used to record ICaL. Results Control group the peak current of ICaLdensity was(-4.99±0.35) pA/pF; H2O2group increased the peak current of ICaLdensity to(-6.97±0.60) pA/pF; Amiodarone group reduced the peak current of ICaLdensity to(-3.16±0.20) pA/pF. Conclusion Amiodarone can reduce ICaLby inhibiting channel activation and recovery after inactivation.