Poly(butylene succinate) (PBS) and its copolymers have attracted much attentions due to their properties of biodegradable polymers, soften temperature, high yield strength and break elongation when comparable to those daily used polyolefin materials. As a result, it has been found applications in biodegradable fibers, packaging materials, injection molded products and films. In order to further improve the elasticity of PBS matrix as a application in agricultural plastic mulching film, the Butyl Glycidyl Ether (BGE) is selected as a branch mononers and correspondingly PBS-bge copolymers is synthesised with different branched ratio by polymerization. Since the rheological properties of polymer under molten state is a way to obtain the information of the processing ability and structure property relationship of materials. There has been a need to investigate the polymer chains structure on the processing ability. In this study, the dynamic viscoelastic is employed to study the rheological properties of neat PBS and PBS-bge copolymers. The results indicated that all copolymers showed high mole weight and well matched the reaction mole ratio. But the PBS-bge copolymers exhibited a higher shear thinning behaviors than neat PBS. And all PBS-bge copolymers exhibited a higher complex viscosity at low frequency indicating network-like structures were formed at the low shear frequency. In addition, the tanδ is remarkable decreased with the introducing of BGE, which reflects that the elasticity of polymer is significantly improved. As a result, the branched modification has improved the ductility and toughness of the material obviously, especially when the branched ratio is more than 15%.