Objective To establish a HPLC method for the determination of emodin in Dabaidu capsule. Methods The chromatographic system was adopted C18 column, using methanol -0.1% phosphoric acid (70∶30) as mobile phase. The content was detected at a waveleng of 254 nm and the flow rate was 1.0 ml/min.Results The emodin have a good tincar rolatim in the range of 6.181 ～ 18.54 μg/ml (r=0.9999), the average recovery rate was 98.93% and RSD = 0.65% (n = 6) . Conclusion The established method is accuracy,sensitive and simple.