In order to promote the practicality and utilization of harvesting robot, a general clamping mechanism was designed. With the virtual prototype built in ADAMS and ANSYS, the clamping mechanism of the harvesting robot for avoiding fruit injury was discussed. Through the deformation stress analysis of citrus, the impact analysis of picked stress was examined and the structure was optimized. Therefore, the parameters of the structure and the minimum amount of clamping （below 2mm in diameter direction) were validated.