In order to meet the piston micro-actuator used in the small-caliber Ammunition Fuze Safety System structural and functional requirements, ANSYS/LS-DYNA finite element software was applied to analyze the structure design of the piston micro-actuator, and the structure and size parameters which affect its performance were determined. The anti-thrust force and setback force of different structural size parameters piston micro-actuators was obtained through the piston micro-actuator performance experimental test. With step height of 0.03 mm, anti-thrust force is 142 N, and the setback force was 38.5 N. The fitting curve and expression of the piston micro-actuator and thrust distance were got under different charges. With thrust distance of 2.0 mm, the minimum thrust is greater than 20 N. Results show that the deviation of the numerical simulation results with experiment values with 15%, indicating that the numerical simulation method can be applied to research micro-actuator function process.