Objective: to study the effects and mechanisms of ultrasonic on ability of learning and memory in Kunming mice. Methods: changing the time of irradiation can get different dose of ultrasonic. Using Morris water maze analyzes the activity of Kunming mice on different time points. Remain the same ultrasonic irradiation time, and find the rule of platform latency by comparing the ultrasonic method with no ultrasonic. According to statistics analyzing related experiments data by SPSS and the theory of ultrasonic biological effects, how ultrasonic affects the ability of learning and memory in mice can be found. Results: small doses of ultrasonic have positive significance on the learning and memory ability in mice .But more than regular doses, the ability of learning and memory will be badly damage. After ultrasonic irradiation, the latency is discrete distribution while no ultrasonic irradiation the latency is stable. Conclusion: ultrasonic has certain effects on the learning and memory ability in Kuming mice. Its mechanism is the mechanical, thermal, cavitation effect of ultrasonic.