By mesns of rotation composite design of quadratic regression,5 mathematical models were constructed in the present paper to study the relationship between the preyed numbers of the rice leaf roller and its predators.The models had also been corrected with several years data investigated in the paddy field.According to these models,the preyed numbers of the rice leaf roller could be estimated by its densities and each predator.Therefore they could be used to forecast the population dynamics of the rice leaf roller.