Using traditional continuous charge blasting method in Zijin Mine is easy to produce powder near the crushing circle of the hole,resulting in substandard ore gradation and waste of resources.Therefore,in order to improve the ore gradation and increase the aggregate products,a blasting test was carried out under the conditions of 0 m,1 m,1.2 m,and 1.5 m in the middle of the air-decked charge blasting technology.Firstly,a limestone model using HJC constitutive relation was established to simulate the actual geological by ANSYS/LS-DYNA finite element software.And then,the damage distribution characteristics of rock mass under different spacing distance conditions were analyzed,and the relatively optimal air spacing charge length was obtained.Finally,the 1.2 m and 1.5 m middle air decking are selected to control the blasting powder rate.The field blasting tests and the comparison of rock gradations under different conditions show that it is effective to reduce the powder rate by adopting the intermediate air decked charge.When the air decking length is 1.5 m,the non-uniformity coefficient Cu and the blasting powder rate can be reduced.Before the technical transformation,the average powder ore rate is about 15.94%,and after the technical transformation,the powder ore rate below 4.75 mm can be reduced to about 9.37%,making the grading to a good level.