Abstract: This research optimized the ultrasonic extraction process for balsam pear saponin to get an extraction method with more convenience and higher efficiency, and could serve as a reference for saponin content comparison among different varieties of balsam pear and industrial production. Single factor experiment was used in preliminary screening the ultrasonic temperature, ultrasonic time and liquid-material ratio for defining appropriate optimization scope, and response surface methodology based on Box-Behnken design was employed in the process optimization designing and experiment. The results showed that under the condition of 400 W ultrasonic power, 40 kHz ultrasonic frequency and 70% ethanol extraction, the optimum extracting condition of total saponin in balsam pear was as follows: the extracting temperature was 60℃, the extracting time was 23 min, the liquid-material ratio was 16:1. The optimized ultrasonic extraction process uses less time and obtains high yield. The saponin content of ‘Ruyu 45’ balsam pear can reach 6.86% with the optimized extracting process.