The soaking and the cooking mechanisms of rice were investigated in terms of the mathematical rate equations in this study. The soaking and the cooking rate were measured by using the weighing method, and the soaking rate was examined at temperatures from 8 -SO"C, and the cooking rate from 70 -98.5"C. The rate equation involved two rate parameters: the reaction rate parameter of the rice component with water and the diffusion rate parameter of water, was assumed. The results showed that the cooking rate was mainly limited by the reaction rate of rice components with water at temperatures from 70 -98S"C, and the equivalent value of the activation energy of the reaction rate was nearly equal to 20 kcal/mol, though the cooking rate was relatively influenced by the diffusion rate of water in the cooked rice layer at 98S"C. In the soaking of rice, the values of the diffusion rate parameter at from 8.0 -50°C were smaller than the values at from 110 -150°C.