In order to reduce throwing soil as fertilizing the field, mathematical model of pricking hole mechanism was built, computer aided analysis software was developed in VB language. Simulation results showed that the effort factors of fertilize related to spraying needle, rocker, angle of spraying needle and rocker, planet carrier and so on. One of the optimum parameters were that, the length of rocker was 197mm, spraying needle was 180mm, angle of spraying needle and rocker was 76°, the initial planet carrier of angle was 31° and the initial angle between the line of connection with planet wheel axle and spraying fertilizer needle’s D and the line of the center connection of planet carrier was -70°. The optimal model was verified to get well effect on pricking hole mechanism.