Abstract: In order to improve the level of monitoring, early warning and comprehensive control of rice blast in Nanchong City, and reduce the harm of rice blast, the methods of GPS and GIS location, systematical monitoring and survey, rice blast resistance variety identification, physiologic variety monitoring and weather data analysis were adopted to study the regionalization, accurate boundary settlement and occurrence and epidemic regularity of the disease. In this study, regionalization and boundary settlement were analyzed for the first time, the primary infection location, occurrence characteristics, trends and characteristics of the disease were verified. There were four epidemic peak periods and the damage areas of the first peak period played a decisive role, the accumulated occurrence area at the end of May was positively correlated with the year occurrence area, and the correlation coefficient was 0.8172. A prediction model of occurrence area based on the disease field rate at the end of boot stage and the disease plant rate at dough stage was established. Through investigation of the causes of blast disease in Nanchong in recent years, the authors found that the internal causes were the decrease or lose of rice blast resistance, the increase of high pathogenicity physiological race and the appearing of stronger pathogenicity physiological race, the external causes were suitable temperature and more overcast and rain and less sunlight. During 2010 to 2015, the short-term forecast accuracy for rice blast in Nanchong was up to 100%, medium-term and long-term forecast accuracy were also up to 98% and 95%, respectively, which increased by 5-15 percentage points compared with that before 1997, thus increased the control effect of rice blast in Nanchong by15%-30%.