A high performance capillary electrophoresis method was established for the determination of indoleacetic acid（IAA） and gibberellic acid-3（GA3） in male floral buds of Populus tomentosa Carr..The samples were extracted with methanol by ultrasonic.Effects of experimental conditions,such as concentration and pH value of buffer,separation voltage,separation teperature and injection time on the separation efficiency were investigated.The optimal conditions were as follows:running buffer:pH 8.0 10 mmol/L borate-2.5 mmol/L SDS,injection time:5 s with a pressure of 50 mbar,determination temperature:25 ℃,applied voltage:22 kV,detection wavelength:200 nm.Under the optimum conditions,good linearities between peak areas and concentrations of IAA and GA3 were found in the ranges of 0.04-0.2 mg/L for IAA and 0.2-1.00 mg/L for GA3,with their correlation coefficients of 0.995 2 and 0.999 8,respectively.Two target analytes could be completely separated in 10 min.With the advantages of simple extraction,fast separation and high accuracy,the proposed method could be simultaneously applied in the determination of IAA and GA3 in plant samples.