The organic modification of silicon dioxide coated aluminum pigment wascarried out using a comb shaped amide modified styrene maleic anhydride copolymer. Themechanism of organic modification of silicon dioxide coated aluminum powder was explored bycombining thermodynamic theory and dispersion stability theory. The changes in zeta potential，water absorption，and gloss before and after organic modification were discussed. Theresults showed that the organic modifier formed an effective coating layer on the surface of thepigment. After organic modification，the zeta potential of aluminum pigment and the metallic luster of the paint film increased，indicating the dispersion stability improvement of thepigment. Adding 3% organic modifier could reduce the water absorption of pigments from 2. 84% to 1. 70%，with a decrease of 40%，further verifying the effectiveness of organic modification of aluminum pigments.