Objective To adopt the capillary electrophoresis(HPCE) for detecting the contents of emodin,chrysophanol and rhein in the extract of rheum officinale.Methods The detection was executed with a fused-silica capillary column(67.4 cm× 75.0 μm,effective length 51.0cm) as the separation column.The buffer solution consisted of 60 mmol/L Na2B4O7,40 mmol/L Na2CO3 and 40 mmol β-cyclodextrin(pH 8.9).The detection wavelength was 254 nm.Results RSD of precision in emodin,chrysophanol and rhein was 1.79％,4.46％ and 2.30％.respectively The linear range of 3 components was 1.1-19.0 mg/mL;the average recovery rates of emodin,chrysophanol and rhein were 100.14 ％,99.65 ％ and 98.44 ％ respectively,RSD was 2.43 ％,2.54 ％ and 2.02％ respectively(n=3).Conclusion The method can be used in the content determination of rheum officinale extract.