Phase separation of quenched critical and off-critical polymer blends of poly (methyl methacrylate) and poly(vinyl acetate) was studied by using light scattering technique. The results show I(q

t) - qm-3-s(q/qm);s(X) -X2/(3 + X8) and X2/(2 + X6) for critical off-critical mixtures

respectively. In the late stage of phase separation

the self-similarity of the structure is preserved and the coarsening processes are one that the domains increase with self-similar.