Iron-base powder metallurgy parts are provided with loose and porous structure, hence acid, alkali and salt may be left in pores of the parts easily during such process as pretreatment, electroplating and passivation. In such case, the plated parts were easily subject to corrosion resistance decrease or coating peeling off. Therefore, sealing pretreatment of pores in iron-base powder metallurgy parts can efficiently improve the corrosion resistance and coating adhesion. A special water-based antirust sealing solution for iron-base powder metallurgy parts was applied to the first sealing before pores pretreatment and second sealing after pretreatment. During the first sealing process, inhibitor and passivation agent in this special antirust solution could diffuse and permeate through the pores, and result in chemical adsorption, passivation or precipitation in pores, which could reduce or avoid acid, alkali and salt residue during pretreatment. During the second process, the passivation and sealing effects of the parts were further improved. For white passivated zinc nickel alloy coatings not subject to second sealing treatment with antirust water solution (barrel plating parts), slight corrosion occurred on the surface after 96 h salt spray test; for the Zn-Ni alloy coating subject to first sealing treatment, slight corrosion occurred after 120 h; for the Zn-Ni alloy coating subject to second sealing treatment, slight corrosion occurred after 240 h. The corrosion resistance and adhesion property are both significantly improved by performing the sealing processes, Zn-Ni coating electroplating and coating passivation.