Abstract: An oligomer was prepared by the reaction of succinic acid with butyl glycol, and a series of copolymers were synthesized by use of the digomer, dimethyl terephthalate and silanol through melt polycondensation. Chemical structure, crystallization-melting behavior, thermal performance, morphology and mechanical properties of the resultant copolymers were characterized by 1H-NMR, 29Si-NMR, differential scanning calorimetry, thermogravimetric analyzer, scanning electronic microscopy and universal testing machine. The results indicated that the copolymers were constituted by PBS as a main chain, silane segments as a chain extender and tougher and PBT bulk as a reinforcement. They not only achieved a liner molecular structure with a high molecular weight but also obtained an improvement in mechanical properties and thermal stability. Moreover, the copolymers exhibited imperfect spherulites due to the fast crystallization rate and lower crystallinity. Owing to a highly flexible silane segment and a rigid PBT segment, the copolymers achieved an increase in tensile strength by a factor of 1.4～2.1, an increase in impact strength by a factor of 4～7, and an increase in elongation at break by a factor of 2～4.