Methyl acrylate has been grafted on the surface of carbon black through hydromethyl group, which was introduced onto carbon black by reaction with formaldehyde in NaOH solution. The copolymerization was initiated by manganese acetylacetonate. Hydrolysis of the grafted chain improved the stability of hydrolyzed grafted carbon black dispersion in water. The grafted carbon black was characterized by AFM. Orthogonal experiment shows that the optimum concentrations of initiator,momomer and carbon black are 12 mmol/L, 0 4 mol/L and 1∶80(mass ratio of carbon black to total mass of the system) respectively in graft copolymeriation.