Amphiphilic block copolymers PEG-〖WTBX〗b〖WTBZ〗-P(St-〖WTBX〗co〖WTBZ〗-VBC) with controllable molecular weight and low polydispersity were synthesized by one-step reversible addition-fragmentation transfer(RAFT). The structure and property of the synthesized amphiphilic copolymers were characterized by GPC, NMR, FT-IR and DSC. The results showed that the number of vinylbenzyl chloride (VBC) units in amphiphilic block copolymers PEG-〖WTBX〗b〖WTBZ〗-P(St-〖WTBX〗co〖WTBZ〗-VBC) can be well tuned by controlling the mole ratio of VBC and Styrene(St). Moreover, the glass transition temperature of PEG-〖WTBX〗b〖WTBZ〗-P(St-〖WTBX〗co〖WTBZ〗-VBC) is gradually increased with the addition of VBC units in block copolymers.