OBJECTIVE To elucidate pharmacokinetics of erianin fat emulsion in rats. METHODS An HPLC-MS method was developed and used to determine the rats plasma concentration of erianin after intravenous injection at single, and dosage multiple dosages which with each two days and each half elimination time(t_1/2) a time administration. RESULTS The parameters of single dosage as 25, 50, 100 mg·kg^-1 of erianin in rats: T1/2β values were 3.66, 3.75 and 3.89 h. AUC_0-12 values were 1 453.0, 3 041.6, 6 731.6 ng·mL^-1·h. AUC_0-∞ values were 1 462.0, 3 077.3, 6 788.7 ng·mL^-1·h. Vd values were 11.67, 10.37 and 3.38 L·kg^-1. CL values were 0.049, 0.089, 0.024 L·kg-1·h^-1. MRT values were 0.18, 0.28, 0.21 h, respectively. The parameters of erianin multiple dosages with 50 mg·kg^-1 administration each two days were similar as the single dosage. However, the T_1/2β value prolonged to 5.43 h, the AUC_(S0)(0-t) elevated to 9 800.8 ng·mL^-1·h, while multiple dosage of 50 mg·kg^-1 each half elimination time. CONCLUSION The pharmacokinetics of erianin fat emulsion with single dosage administration in rats had dose-concentration linearity, the T_1/2β values had no change within the dose range. It suggested that erianin fat emulsion pharmacokinetics was in accordance with two-compartment open model, and its elimination in rats obey with linear kinetics. However, administration with each t_1/2 a time at the dose of 50 mg·kg^-1 of erianin, its elimination obeyed nonlinear kinetics.