Sulfonated poly(styrene-co-divinylbenzene) resins (SPS) present many advantages，so they have been widely studied in laboratory and applied in industrial processes.To lower their price for potential applications，low-price sulfonating agents are used to convert polystyrene (PS) to SPS.The traditional sulfonating agents are sulphuric acid，fuming sulfuric acid and SO3，but sulphuric acid leads to high cost and pollution，and SO3 makes the sulfonation reaction violent，in which local overheating，oxidation and coking are observed.This work reports a new method that SPS is synthesized by PS-DVB and chlorosulfonic acid (HSO3Cl).The influence factors on the sulfonation reaction，such as reaction time，temperature，solvents，amount of sulfonating agent，were investigated.Some results are obtained.(1) The solvent may be chloroform or carbon tetrachloride (CCl4).(2) The optimized reaction time is 30 min and the optimized mole ratio of HSO3Cl to PS is 1∶1.(3) By controlling the amount of sulfonating agent and reaction time，the sulfonic loading can be controlled in the range of 0—5.4 mmol·g-1.When HSO3Cl is used as the sulfonating agent，HCl is easy to remove，making the sulfonation reaction more complete.This method has many advantages over the traditional process，such as low temperature，short reaction time，more complete sulfonation and friendly environment and provides potential use of sulfonation products.