Some comparative prediction experiments with different physics parameterization schemes are conducted on precipitation over the middle reaches of the Changjiang River in flood season. The results show that different physic parameterization schemes can lead to different forecasting results, which becomes more evident in predicting highergrade precipitation. In the experiments, the forecasting combined the Grell cumulus parameterization scheme with the Blackadar planetary boundary layer scheme is better than others. However, for a certain case, it is uncertain which scheme is better. The result of ensemble mean prediction is relatively stable and superior to most single predictions. The improvements in precipitation prediction can be seen mainly in the situation with the rainfall being less than 50 mm.