At the apple orchards in main producing areas in Sanmenxia City choosed two locations that the yield management level were as research object among five experiment spot,the impact of bagging on fruit calyx opening rate,the incidence of heart mildew were investigated and analyed.The results showed that the rate of calyx tube opened and moldy core disease were significantly different.The rate of calyx tube opened rose was 21.0%～47.0% and the rate of moldy core rose was 14.0%～46.0% respectively,after the fruits were bagged.Farther more,the rate of moldy core reached 32.5%～89.4% in the calyx tube opened fruits,compared with 0%～13.0% in the calyx tube shutdown fruits after fruit bagging.So the rise of moldy core rate was closely related to the calyx tube opened after fruit bagging and controlling method was quite different from other diseases.