The H-shaped copolymers (PSt)(2)PEG(PSt)(2), which are constructed by attaching two polystyrene branches to both ends of poly(ethylene glycol), were synthesized by atom transfer radical polymerization (ATRP). The synthetic strategy involves the synthesis of 2,2-bis(methylene alpha-bromopropionate) propionyl chloride, the preparation of 2,2-bis(methylene alpha-bromopropionate) propionyl terminated poly(ethylene glycol) (BMBP-PEG-BMBP), and then ATRP of styrene at 110 degreesC using BMBP-PEG-BMBP/CuBr/2,2'-bipyridine as the initiating system. The structure of the H-shaped copolymers was confirmed by NMR spectroscopy and GPC measurements. The thermal behavior of the H-shaped copolymers was investigated by differential scanning calorimeter. The high molecular weight poly(ethylene glycol) in the H-shaped copolymers shows higher crystalline ability, and the degree of crystallinity, X-c, decreases with the decrease of PEG weight fraction in the copolymers.