Abstract:The errors of 24 hour and 48 hour area rainfall forecast of Tianjin Meteorological Observatory and Hebei Meteorological Observatory in the Haihe river basin from July to August 2002 are analyzed. Based on fuzzy comprehensive judgment method, the two observatories′ fuzzy grades are calculated. The results show that area rainfall forecasts in the Haihe river basin have much more reliability, which are much more useful as a initial values of hydrologic model. The results also show that in the observatories′ forecast regions, the less the area, the higher the forecast accuracy, and the number 80% (or 80) is an objective and believable value for evaluating the forecast effects of area rainfall.