This paper aims to develop a LC-MS method to determine evodiamine and rutaecarpine in rats plasma simultaneously.The method was employed to investigate pharmacokinetics of evodiamine and rutaecarpine.Blood samples were collected in different time after oral administration with the extracts of Evodiae Fructus; the plasma concentration of evodiamine and rutaecarpine was determined by LC-MS, and pharmacokinetic parameters were calculated by WinNonlin 5.1 software.The linear ranges of evodiamine and rutaecarpine were 0.5-100 μg·L-1(r=0.9959), 1-200 μg·L-1(r=0.9993) resp.The average recoveries exceeded 76%(n=5), and the precisions of inner-day and inter-day were less than 15%.The pharmacokinetics parameters AUC, t1/2, CL_F of evodiamine were: (2 215.24±414.49), (4 230.62±753.77), (13 219.21±3 740.95) min·ng-1·mL-1; (146.57±38.38), (114.38±14.65), (163.37±8.83) min; (184 607.29±32 502.21), (192 878.22±31 897.37), (19 3224.63±62 278.74) mL·min-1.The pharmacokinetics parameters AUC, t1/2, CL_F of rutaecarpine were (2 283.53±298.51), (4 424.84±276.95), (14 239.93±3648.27) min·ng-1·mL-1; (167.10±15.82), (131.58±20.07), (144.41±13.65) min;(1 177 340.54±2 4942.21), (181 262.92±11 162.22), (177 508.10±52 611.80) mL·min-1.The method described in this report has high sensitivity and selectivity, and was suitable for pharmacokinetic studies of evodiamine and rutaecarpine.The kinetic process of evodiamine and rutaecarpine in rats in vivo yielded to be one-compartment model.