Abstract: In order to elucidate the effects of rainfall in different months on bagged apple black-rot disease, we studied the incidence of‘Red Fuji’apple black-rot disease in Yantai Shandong, Baishui Shanxi and Sanmenxia Henan in 2011, 2012, 2013. The results showed that the incidence of bagged apple black-rot disease varied in different years. It was the highest in 2011 and the lowest in 2013. The incidence of apple black-rot disease also varied in different areas. It showed that disease incidence gradually reduced from east to west and followed this order: Yantai Shandong > Baishui Shanxi > Sanmenxia Henan. The rainfall in January, April, May and July had negative correlation with the incidence of apple black-rot disease, but the correlations were not significant. The rainfall in other months had positive correlation with the incidence of apple black-rot disease. Especially in September the rainfall significantly affected the incidence of apple black-rot disease, the Pearson correlation coefficient was 0.861(P<0.01). Pearson correlation coefficient of average rainfall of August and September and the incidence of apple black-rot disease was 0.862(P<0.01). The rainfall intensity in January, July and October had negative correlation with the incidence of apple black-rot disease. However，there was no associated significance. Rainfall intensity in other months had positive correlation with the incidence of apple black-rot disease. In June, August and September, the rainfall intensity significantly affected the incidence of apple black-rot disease (P<0.01). Moreover, Pearson correlation coefficient of average rainfall intensity of August and September and the incidence of apple black-rot disease was 0.907(P<0.01). So the rainfall and rainfall intensity both have significant positive correlation with the incidence of apple black-rot disease in August and September, which were the critical period of the apple black-rot disease control.