Abstract: In order to assure good reliability for liquid fertilizer applicator in high working speed, the pricking hole mechanism of liquid fertilizer applicator was taken as research object, and the maximum force and undulation force of x and y directions of sun gear were taken as objective function. Optimization results of kinematics was used as constraint conditions of objective function, and the dynamics optimization software was developed based on the improved “interspecies competition” genetic algorithm by using Visual Basic 6.0 software. Optimized parameters were obtained by this software, where the initial angle between the line connecting spraying-fertilizer needle-tip or planet wheel axle and planet frame is -42o, and the initial angular of planet frame is 45o, and the distance between spraying-fertilizer needle-tip and the planetary gear axle center is 285 mm. According to the dynamic optimization results, the pricking hole mechanism of liquid fertilizer applicator was designed and simulated by using Pro/E and ADAMS. The simulation results showed that the pricking hole mechanism with the optimized parameters can satisfy the operation requirements and has good mechanical properties.