The effect of mixing ratio of solvents, tetrachloroethane and nitrobenzene, on the induced autocrosslinking reaction of chloromethylpolystyrene(PCMS) in the presence of the mixed solvent was investigated. The solvent mixing ratio of let- rachloroethane/nitrobenzene does not show any correlation with the degree of autocrosslinking. Several types of chlorome- thylstyrene(CMS)styrene(St) copolymers were autocrosslinked starting from different composition ratios of CMS and St. It has also been found that the composition ratio of CMS and St does not have significant effect on the degree of autocrosslinking of CMS-SI copolymer.