Amphiphilic triblock copolymer mPEG b P1 b mPEG,with disulfide bond in the main chain of the hydrophobic block,was prepared from cystamine dihydrochloride,allyl chloroformate,1,6 hexanedithiol and monomethoxy poly (ethylene glycol) with a thiol end group through thiolene click chemistry method. Self assembly of the obtained mPEG b P1 b mPEG was further investigated. The results showed that the critical micelle concentration of the amphiphilic block polymer was 0.032 mg/mL,and the average diameter of the micelle was about 61.3 nm. The loaded model drug Nile Red could be released from the micelles in the presence of DTT,indicating the reduction responsiveness of the obtained amphiphilic copolymer. Therefore,these findings suggested the potentials of the amphiphilic copolymers as smart intracellular drug delivery systems.