Based on the data, collected in Haidian district in 2006, of the incid ence of preday’s infectious diarrhoea and the weather condition, a forecastin g model of infectious diarrhea medicalmeteorological grade and risk level evalu a tion model were set up by using multiple regression probability grade analysis. The Pearson correlation coefficient of the incidence and the atmospheric vapor p ressure was 0.8340. The proportion of variance contribution of vapor pressure wa s highest (70.5%). Mean wind speed and diurnal temperature had higher proportion of variance contribution than other factors. If the difference between the fore casted grade and actual grade is no more than 1, the forecasted grade of the inf ectious diarrhoea disease medicalmeteorological grade forecast models would be defined as proper grade. The mean ratio of proper forecasted grade forecast mod els was 98.5%, and the exact proper rate (for 6 time periods) was 62.9～66.4％. It is concluded that the forecasting model of infectious diarrhoea disease medic almeteorological grade forecast and the risk level evaluation model could well forecast the incident of infectious disease during Bingjing Olympic Games, and be helpful for the Center of Disease Prevention and Control (CDC) to provide pu blic health services for citizens according to the outcomes of the models.