Abstract: An analytical method was established for determination of lorcainide hydrochloride concentration in serum using high performance liquid chromatography(HPL.The stainless steel column was 200 mm × 5. 0 mm ID, packed with YWG C₁₈H₃₇,5μm, The mobile phase consisted of methanol-water-0. 625 mol·L^-1 ammonium acetate.(86:13:1v/v),adjusted to the pH 8. 0 with ammonium hydroxide. The flow rate was 1 ml· min^-1, using diltiazem as internal standard.Chromatography was performed with ultraviolet detector at 226 nm. The recoveries of lorcainide hydrochloride at 40,200 and 400μg,L^-1 were 95.85%, 100.63%and 100.09%, respectively.The within-day and day-to-day RSD of the determinations at concentrations of 100,260,400 and 800μg·L^-1 were less than 7%. Linear calibration curve for lorcainide hydrochloride was measured within the range of 20 to 800μg·L^-1 with correlation coefficient of 0.9996. The detection limit was 5μg·L^-1 in serum. The HPLC method described is suitable for clinical monitoring and pharmacokinetic study of lorcainide hydrochloride.