Abstract: OBJECTIVE To establish a UPLC-MS/MS method for rapid determination of apatinib concentration in rat plasma and apply to pharmacokinetics study. METHODS Rat plasma samples were prepared with acetonitrile to precipitate the protein. The apatinib concentration in rat plasma was determined by liquid chromatography-mass spectrometry. The mobile phase was acetonitrile-water (containing 0.1% formic acid). Gradient elution with a flow rate of 0.3 mL·min^-1, column temperature was 40℃, chlorzoxazone was used as internal standard. Mass spectrometry conditions:Electrospray ionization source(ESI), negative ion detection mode, detection pairs were m/z 396.2→210.0 and m/z 396.2→158.0 for apatinib, m/z 168.0→132.0 for chlorzoxazone. RESULTS The retention time of apatinib and internal standard chlorzoxazone were 1.07 min and 1.40 min, respectively. The linear range was 10 to 2 000 ng·mL^-1 (r²=0.993) and the limit of quantification was 1 ng·mL^-1. The accuracy of the method was in the range of 90.65%-111.50%, and the matrix effect was 89.14%-104.65%. Mean recoveries of apatinib in rat plasma were >86%. RSD of intra-day and inter-day precision were both <10%. The RSDs of stabilities of 24 h kept in room temperature, froze-thaw 2 times, 30 d froze in -80℃ were all<10%. Pharmacokinetic study showed that after the rats received a single administration of apatinib with 76.5 mg·kg^-1, the AUC_(0-t) was (6 114.41±645.99) ng·mL^-1·h, and CL_z/F was (12.21±1.08) L·h^-1·kg^-1, V_z/F was (75.70±38) L·kg^-1, T_1/2 was (4.23±1.94) h, T_max was (2±0.71) h, C_max was (1 377.7±284.54)μg·L^-1. CONCLUSION The method established is easy to operate, reproducible, accurate and reliable. It is suitable for the determination of apatinib concentration in plasma and can applied to its pharmacokinetics study.