Abstract: The perforative cracking holes(in the direction of thickness)of 3003 alloy during hot rolling were analyzed by means of SEM, EDS and metallographic microscope.The results show that the main reason for cracking is that the coarse hard phase exists in the ingot, and causes the stress concentration during deformation, finally the hard phase breaks to form a crack.According to the cause of cracking, the process improvement and preventive measures of 610 ℃×6 h homogenization treatment was put forward.