OBJECTIVE：To establish a method for simultaneous determination of andrographlide and dehydroandrographolide in Ganmaoqing tablet. METHODS： HPLC was performed on the column of Thermo BDS C18 with mobile phase of mathanol-water at a flow rate of 1.0 ml/min， detection wavelength was 225 nm for andrographlide and 254 nm for dehydroandrographolide， column temperature was 30 ℃， and injection volume was 10 μl. RESULTS：The linear range was 2.25-45.00 μg/ml for andrographlide（r＝0.999 8） and 1.00-20.00 μg/ml for dehydroandrographolid（r＝0.999 0）； RSDs of precision， stability and reproducibility tests were no more than 0.8％； average recoveries were 96.96％-99.80％（n＝9） and 96.79％-100.65％（n＝9）. CONCLUSIONS：The method is simple， accurate and reliable， and can be used for the quality control of andrographlide and dehydroandrographolide in Ganmaoqing tablet.