Abstract: Three chlorostyrene strongly acidic cation exchange resins were prepared from o-, m-, p-chorostyrene and divinylbenzene. The thermal stability of o-chlorostyrene strongly acidic cation exchange resin was the highest. In water at 170℃ the degradation of the prepared resin was less than 14.0% in 100 hours, and degradation rate was 0.0028%/h. In the transalkylation of dinonanylphenol with phenol by using the prepared resin as catalyst, the conversion of dinonanylphenol was more than 99%, and the resin had good stability in this reaction system.