Abstract: Fruit picking mechanism plays an important role in reducing cost and improving efficiency of fruit picking.Foreign researchers have made a lot of in-depth research for picking technology，however，this kind of research is still insufficient in our country.Vibration model system of picking mechanism was analyzed.Parameter calculation of the vibration system was giren a simple introduction.Through analyzing the motion law of fruit while vibrated，models of fruit movement and its dynamic differential equation were established.Furthermore，some theoretical basis about vibration motion and state of forces when fruits were vibrated were provided.