Abstract: In order to analyze the relationship between the downy mildew of wine grape and meteorological conditions in Changli, the predictive equation was established to offer technical support for the prediction of downy mildew using short-term weather forecast. The observing data of downy mildew and the meteorological factors such as temperature, humidity and rainfall in recent 5 years (2009-2013) were used, each factor of 7 days before downy mildew occurrence was analyzed, and the multiple regression analysis was performed to gain the regression equation. The results showed that: low temperature and high humidity were the important condition for the occurrence and prevalence of downy mildew; to the wine grape in Changli, when the temperature reached 22-26℃ within a week, the relative humidity could reach more than 80% and a rainfall would happen, meanwhile when the Y value calculated according to the prediction model was between 0.95-1.5, downy mildew would happen easily. In this paper, the predictive model of downy mildew of wine grape in Changli was obtained, which would play a very positive role in predicting the onset of disease, strengthening the control of disease, and helping meteorological department to serve wine grape growers better.