Abstract: Based on the principle of the acoustic levitation, by changing the shape of the excitation and the reflection side of tile single axis ultrasonic levitation system to convex, the circular clamping force is produced surrounding the acoustic levitation regions, and the stability of sample suspension is improved in the standing wave field. By tile Finite Difference Time Domain (FDTD) method, we studied the force distribution in different resonant cavity, tile factors affecting of the suspension force, and optimized the circular clamping force and the suspension force. The experiment results and theoretical analysis indicate that the stability of the ordinary single axis acoustic levitation system can be improved by the circular clamping force of our convex side system