Abstract: A high performance liquid chromatographic method (ultraviolet detection) for the determination of flecainide concentration in human plasma was reported. Flurazepam (dalmadorm) was used as the internal standard. A mixture of methanol and deionized water containing ion paired reagent served as the mobile phase. The regression equation of flecainide was. Y=0.0017x+ 0.0131,r= 0.9975. The extraction recoveries exceeded 94%, and the coefficients of variation (both within the same day and in different days) were less than 5 %. The pharmacokinetic parameters in Chinese volunteers after taking flecainide were: Ka = 0.908h^-1, T_1/2 = 8.131h, peats time = 3.487h,AUC=441.8ng · h/ml.The mean plasma concentration of flecainide in cases responded well to this drug was 423.6±227.4ng/ml.