Abstract: OBJECTIVE To investigate the differences of pharmacokinetic characteristics between sodium valproate and magnesium valproate in rats, and provide reference for clinical rational use of drugs. METHODS SD rats were randomly divided into 2 groups and gavaged with sodium valproate and magnesium valproate respectively. Blood was taken from the orbit at different time points. An HPLC method was established to determinate the blood concentration of valproic acid in serum. The pharmacokinetic parameters of sodium valproate and magnesium valproate in rats were calculated and compared. RESULTS The HPLC method showed a good specificity, and a good linearity was obtained over the range of 10.00-110.00 μg·mL^-1. The mean recovery and precision values were favorable. The pharmacokinetic parameters of sodium valproate and magnesium valproate were as follows:T_1/2 was (14.02±3.86)h and (12.11±1.95)h; T_max was (3.67±0.58)h and (2.67±0.26)h; C_max was (67.10±10.87)μg·mL^-1 and (75.67±12.94)μg·mL^-1; AUC_(0-t) was (969.86±72.08) μg·mL^-1·h and (1 093.56±48.69)μg·mL^-1·h; AUC_(0-∞) was (1 178.10±185.29) μg·mL^-1·h and (1 279.35±109.18)μg·mL^-1·h; MRT_0-t was (10.73±2.05)h and (13.06±3.24)h; V_d was (16.31±2.18)L and (23.47±2.19)L; CL was (0.056 3±0.009)L·h^-1 and (0.051 1±0.004)L·h^-1. CONCLUSION Compared with sodium valproate, magnesium valproate showed some advantages in pharmacokinetics in rats, may be a more therapeutic advantage of valproic acid salt.