Abstract: Psoralen and isopsoralen are the representative active components in Psoralea corylifolia L. The total yield of them was used as the criterion for optimization of ultrasonic extraction conditions of active components from P.corylifolia. Extracting time, liquid-solid ratio and ultrasonic power were selected as casual factors. Based on single-factor experiments, three-factor-three-level Box-Behnken central composite experiment design method was applied. Total yield of psoralen and isopsoralen was used as response values. Response surface analysis methodology (RSM) was used for analysis of the results of these experiments. The optimum conditions of ultrasonic extraction were as follows:extraction time 47.5 min, liquid-solid ratio 5.6:1 (mL:g) extracting solution 20 mL, and ultrasonic power 330 W. Under these conditions, total yield of psoralen and isopsoralen was 1.043%, validation value was 1.047%, relative error was 0.384%, which demonstrated the feasibility of this method.