Abstract: The test is on the basis of the on-site process in the Oxygen pressure acid leaching workshop of Danxia smelter.After technical improvement,the content of －40μm can be increased from 65% to 83% through the secondary vertical agitating mill.The pulp before and after grinding was taken respectively as raw materials of leaching,and then small oxygen pressure acid leaching sphalerite experiment was carried out in the laboratory.The experimental results show that,as the size of leaching material become smaller,the leaching efficiency become higher.Along with the diminution of the size of leaching material,the residue rate of leaching residue reduce,the grade of Zn in leaching residue also reduce,that brings recovery ratio’s increase of Zn resources,reduces the waste of resources.100000 tons of zinc ingots can be produced per annum in Danxia smelter former,and the prices of Zn ingot about 14500 yuan per ton,if the leaching efficiency increased by 2%,earnings of Danxia smelter will increase around 29 million each year.