Abstract: For the purpose of effectively prevent plum fruit（Prunus salicina L.）cracking disease，suppress the fruits of moisture absorption and GA₃ promote epidermal growth angles from ethephon. The optimum combination of the screening reagent concentration，composition，dosage and administration period，comparing each treatment differences matter content in the combination of fruit and peel the cell structure. Thirty days before harvest，painstaking sprayed ethephon（0.5 g · L^-1）one time，then sprayed GA₃（0.5 g · L^-1）one time the day after. After this，the results shows that the cracking rate is only 0.4%（control 21.2%）and control efficiency is 98.13%. The contents of soluble sugar and vitamin C are significantly higher than the control group. Titratable acid and water content are significantly lower than the control group. The core reason of peel splitting is that the compared epidermal cells is relatively small and several cells in the cortical is relatively great and the growth rates are not synchronized. By reducing moisture，using ethephon could be narrow under cortical cells，and translate into a horizontal strip from a vertical strip while the longitudinal cracking of skin is not easy. GA₃ significantly increase the epidermal cells. Due to reducing water content，the epidermal cells and under cortical cells are increasedsimultaneously. Using ethephon alone could lead premature fruits drop and reduce the sugar content of fruits. With combination of GA₃，premature fruits drop can be prevented and sugar content can be increase.

Key words: plum, fruit cracking, prevention, ethephon, gibberellin