OBJECTIVE To establish a HPCE method for the determination of aminophylline illegally adulterated into traditional Chinese anti-asthma medicines.METHODS The running buffer was 100 mmol·L^-1phosphate buffer solution(pH was adjusted to 7.0 with phosphoric acid).The separation was performed on a fused-silica capillary(50 μm×48 cm,40 cm of effective length).The detection wavelength was set at 270 nm and(5 kPa×10 s) pressure injection was used.Internal calibration method was used for the quantitative analysis.RESULTS Aminophylline was found in 2 samples of traditional Chinese anti-asthma medicines.The linear calibration for Aminophylline was obtained in the range of 10～250 mg·L^-1(r=0.999 6),and the average recovery was 98.05% with RSD of 1.32%.CONCLUSION The method was proved to be selective,accurate and suitable for the detection of aminophylline illegally adulterated into traditional Chinese anti-asthma medicines.