Abstract: A model related to 8 climatic factors for forecasting white rust disease in Dwamp Morningghgy (DM) was proposed.The determinants are pathogen amount,rainfall,night temperature and effectively accumulative temperature.The model is able to forecast the exponent of lesion will occur in seven days.If there are no rains,the lesion exponent is zero.When the night temperature is less than 23℃ after typhoon,the lesion exponent ascends.While in the season of plum rain and fungi amount is higher than 0.1 stack/plant,the lesion exponent sharply rises.It can also forecast the production of Peranospora and Phytophthora in vegetables with the model and provide reliable and high-sensitive data.