Objective To develop a simple method of determination of sorafenib in serum by reversed-phase high performance liquid chromatography (RP-HPLC) and to explore its application in sorafenib therapeutic drug monitoring (TDM).Methods Sorafenib extracted by ethyl ether-petroleum (9∶1) with internal standard of erlotinib from serum was wiped off in 60 ℃ water bath.Sorafenib was redissolved by mobile buffer and analyzed by 40 μl.Chromatographic column was Symmetry Rp18 (5 μm,4.6 mm×250 mm,waters) column in normal temperature.The mobile buffer was 28 mmol/L acetate buffer (pH 5.8)-acetonitrile (37∶63).Sorafenib and erlotinib were detected in 249 nm and 335 nm,respectively.Results The concentration range of sorafenib was 0.50-20.00 μg/ml (r =0.9999).The within-day and between-day accuracies of sorafenib were less than 4.77 ％ and 8.79 ％,respectively.The average recovery rate was 98.48 ％.Sorafenib was stable in serum or after extraction.The concentrations of sorafenib in two patients were detected.Conclusion Detection of sorafenib in serum by RP-HPLC is simple and accurate,which is available to determine sorafenib in serum.The TDM of sorafenib has clinical significance.