Because andrographis has a long history of folk medicine in Southeast Asian countries with antibacterial, antipyretic, antineoplastic, anti-inflammatory, cardioprotective effect and so on, the areas where andrographolia is introduced and cultivated are mainly concentrated. Espically andrographolide, neoandrographolide, andrographiside, homoandrographolide, andrographane, andrographanin, andrographone and andrographosterol that is concentrated in the leaves of the plant play the main medical role of andrographis. Of the above chemicals, andrographolide is the major bioactive constituent responsible for variety of activities. Leaves and stems of plant are used for extracting active phytochemicals; roots are used rarely. In this study, improved the extractability of andrographolide from the A. paniculata by ultrasonic assisted extraction, the optimum condition for extracted the andrographolide is determined by response surface experiment and detected the extractability of andrographolide under the optimum condition. By single factor analysis and response surface experiments, the optimum conditions for extracted the andrographolide were the extraction solution concentration 62.8%, the ultrasonic extraction time 59min, the ratio of solid to liquid 1:10.5 and the extraction temperature 62?. Investigate the andrographolide extractability in the optimun extraction condition by HPLC were increased from 2.27% to 3.28%.