Abstract:The operation of AREM2.3 in Wuhan Institute of Heavy Rain, CMA, in the flood season of 2005 is steady. The TS scores of the precipitation forecast are calcul ated in various areas, such as, the middle and lower reaches of the Changjiang R iver, South China, North China, Northeast China, Southwest China and Hubei Provi nce in flood season (June, July and August). The fail rate, false rate, predicti ng deviation of the whole China in flood season are calculated.The comparison b etween the forecast and real rain field is made. And the TS scores of important rainfall processes of those areas are calculated. The evaluation of the model prediction is made by comparin g with the persistent forecast. It indicates that th e prediction of AREM2.3 in the flood season of 2005 is steady in 48 hours, and A REM2.3 has relative high prediction ability for rain in the middle and lower rea ches of the Changjiang River, South China, North China, Northeast China, Southwe st China, Hubei Province and the whole China, but the prediction for heavy rain centers is not perfect, AREM2.3 has high prediction ability for meteorological e lements in high level, too, its predicting ability for 500hPa height is better than that for 500hPa temperature. 