The kinetics of thermal degradation on blend of paper sludge and styrene copolymers. The thermal analysis at various heating rate, pyrolysis gas chromatography and infra-red spectroscopy at isothermal temperature. The values of activation energy were 23-64 kcal/mol by derivative method and 18-61 kcal/mol by integral method. The themal degradation of PS/paper sludge was main chain scissin, ABS and SAN/paper sludge were random chain scission.