In order to further understand the relationship between the breeding and widespread epidemic of gray mold at flowering stage and meteorological conditions in southeast Guizhou, and provide a better reference for the prevention and control of gray mold and blueberry production, the classification index of gray mold was determined according to the occurrence degree of gray mold in the past 10 years. Based on the daily precipitation, temperature, relative humidity and other meteorological observation data of automatic weather stations in Longbeng, Guangming Village, Xuanwei Town, Majiang County, Wukaping, Longshan Town and Xingren Town, Danzhai County, the occurrence degree of gray mildew and meteorological factors in the main blueberry growing areas of southeast Guizhou province were analyzed. The characteristics and effects of meteorological elements in April of 2014, 2016 and 2019 were analyzed. The results show that the blueberry flowering period was basically consistent with the temperature conditions required for the occurrence of gray mold, and the most suitable temperature was 15~20 ℃. The high humidity condition caused by precipitation is the decisive condition for the incidence of blueberry gray mold. The occurrence degree of gray mold has a very significant positive correlation with the relative humidity of the air, the number of precipitation days and the number of days of daytime precipitation. The occurrence level of gray mold varies with the number of precipitation days and relative. The increase in humidity is aggravated. When the number of precipitation days＞22 d, and the longest continuous precipitation days＞13 d, meanwhile the number of daytime precipitation days＞11 d, and the longest continuous precipitation days＞3 d during the olay, the gray mold susceptibility rate can reach 50%~70%, that is, moderate to severe degree of infection; when the number of precipitation days＞23 d, and the longest continuous precipitation days＞11 d, meanwhile the number of daytime precipitation days＞16 d, and the longest continuous precipitation days＞9d during the day, the gray mold susceptibility rate can reach 70%~90%, that is, serious grade infection degree; when the average relative humidity is more than 88% and the duration is more than 11 days, it may induce a wide range of moderate to severe gray mold; when the average relative humidity is more than 90% and the duration is more than 14 days, it may be induce a wide range of severe gray mold.