A prediction model of rainfall erosion and sediment yield of a watershed for single rainstorm event is one of key study issues of soil erosion at home and abroad. On the basis of the two characteristic values of flood hydrograph, i.e. peak discharge modulus and runoff depth, the concept of watershed runoff erosion power for single rainstorm event was proposed. According to the historically observed data of runoff and sediment in single rainstorm event of Chabagou watershed during the period from 1959 to 1990, the correlation of runoff erosion power and watershed sediment transport modulus was systematically analyzed. Then, the prediction model of sediment transport for single rainstorm event of Chabagou watershed based on runoff erosion power was established and validated. The results indicated that an extremely significant power function correlation existed between runoff erosion power and watershed sediment transport modulus, and the simulated values of sediment transport modulus from the established model for single rainstorm event during the period from 1981 to 1990 were in good accordance with the observed ones.