The effects of the friction force between crystalline and surface of the ingot, cooling water pressure on the quality of the 5052 alloy ingot have been examined. The microstructure of the subsurface under different processing was observed by a polarized light microscope, and the chemical compositions of the segregation area were detected by EDAX. The results indicate that the liquid aluminum breakout can be effectively eliminated by polishing crystalline, applying lubricant oil on the crystalline wall and increasing cooling water pressure during pouring. In addition, the surface macro-segregation can be obviously restrained by increasing the cooling pressure up to 0.20 MPa.