Abstract: In order to investigate the injury mechanism and laws on red bayberry picked by mechanical arms, based on usual mechanical damage forms such as compression, clamp and fall on under the condition of a robot manipulator picking fruits, mechanical damage experimental program was designed, biological traits of phenotype and ripening degree of red bayberry was analyzed. According to the model theory of elastic mechanics on contact between ball and plane and the test data, biomechanical characteristics on red bayberry fruits were deduced. The results analysis could obtain the elastic coefficient C, most contact stress q and characteristic equations and relation curves about several kinds of mechanical damage of red bayberry fruit. This will provide some references for the design and picking control about manipulator of robot for harvesting red bayberry robot.