The dynamics of copolymerization system of N phenyl maleimide with styrene was systematically studied. Methyl phenyl as solvent, polymerization speed equation is R P=k[I] 0.62 [M],We also testified the overall apparent copolymerization energy of four N p substituted phenyl maleimides with styrene, which confirmed the polymerization activity of four monomers and the existence of CTC complex.