During harvesting, handling and transporting, injury of rice grain is not only due to size of the force acting on it but also the number of the loading cycles. The hysteresis energy consuming behavior of rice grain was studied by means of experiments. An investigation on the principles of grain injury was made. The multiply elements quadratic model between the load amplitude, number of the load cycles and the injury percentage of rice grain was developed. Statistical value F was made in order to prove the correctness of the multiply element quadratic model. The relationship between the load amplitude and number of the load cycles was obtained when injury percentage of rice grain was equal to 1%, which provided a base for designs of harvesting, handling and transporting devices.