Abstract: OBJECTIVE To establish a method to determine the concentration of Phenobarbital(PB), phenytoin-sodium(PT) and carbamazepine(CBZ) in the human plasma，and determine the samples in our hospital with this method. METHODS The high performance liquid chromatography (HPLC) was used. The analysis conditions were as follows: acetonitrile-buffer salt solution (30∶70) as mobile phase, column oven temperature 37℃, wavelength 220 nm and flow rate 0.7 mL·min-1. Internal standard method was developed to analyze the content of drugs, and normalization method was developed to analyze the content of impurity. RESULTS The linear ranges were 4.58-75.88 mg·L-1, 2.25-35.95 mg·L-1 and 1.26-20.08 mg·L-1 for PB , PT and CBZ, respectively. The RSD within-day and between-days were both less than 10.0%. The average rate of recovery can be controlled in 85%-115%. CONCLUSION This method is simple, rapid, stable, with good accuracy, precision and high sensitivity.