A method for treating and phosphatizing a metal board without using acid includes the following steps: performing a degreasing step to remove grease and dirt from a surface of the metal board with a degreasing agent; performing a blast-peening step by blasting and peening polygon blast-peening granules on the metal board through a centrifugal impeller to remove an oxidized layer; performing a washing step to clean remaining powders from the metal board after the blast-peening step; performing a phosphatizing step to form a protective phosphate coating on the metal board; performing another washing step to wash off remaining phosphatizing agents from the metal board; performing a rustproofing step to apply a rustproofing agent on the metal board; and performing a drying step to dry the metal board.