Abstract: From the perspective of the weather patterns of wheat stripe rust's infection, proliferation and spreading, this article analyses the causes of a severe outbreak of this disease in Chengdu area in 2009. These eauses include:a mild and moist autumn, a warm and dew-rich winter and a temperate and rainy spring. The initial summary of the required weather condition for the outbreak of wheat strip rust arc as follows:temperature ≥ 10℃,precipitation ≥ 0.5mm for more than 10 days straight. When these conditions are met, wheat strip rust infection is easily induced. This article can be a good scientific reference in preventing and forecasting wheat strip rust outbreaks in Chengdu area.