Chloromethylation of crosslinked polystyrene resin matrix has been carried out in various organic solvents such as dichloroethane, tetrachloroethane, nitrobenzone, and cyclohexane. The results obtained are as follows. 1. Dichloroethane is a universal solvent in chloromethylation, which is independent on crosslinking agent being used and density of polystyrene. 2. Tetrachloroethane and nitrobenzene acted exclusively on EGD, BDD-crosslinked polystyrene particularly effective for highly crosslinked matrix (8%, 12% crosslinking). 3. In the case of nitrobenzene which has high dielectric constant($varepsilon$), considerable autocrosslinking has been accompanied. As the result, it has been proved that the specific dielectric constant of solvent directly influence on autocrosslinking. 4. EGD, BDD crosslinked polystyrene of low crosslinking density was readily autocrosslinked, compared to DVB-crosslinked polystyrene. 5. Only low chlorine content was achieved in cyclohexane was observed due to low swelling ability of cyclohexane.