This work aims to evaluate the in uence of the incorporation of oyster shell powder (OSP) on the mechanical properties, thermal performance and crystallization behavior of green poly (butylene succinate) (PBS) composites by regulating the dispersed oyster shell power with the silane coupling agent. In the present study, fully biodegradable PBS composites have been successfully prepared by virtue of the melt blending with γ-Glycidoxypropyltrimethoxysilane (KH560) grafted oyster shell power namely OSP@KH560, enhancing the mechanical properties and thermal performance of the result materials. The incorporation of 20wt% OSP@KH560 into the composite promotes a dramatic increase of 48.1% in modulus of PBS composite. The results from thermogravimetric analysis (TGA) show that thermal stabilities of PBS composites gradually increase with increasing the amount of OSF@KH560. By adding 30wt% OSP@KH560, the initial decomposition temperature of the PBS composite increase by 15℃. The DSC results demonstrate that the addition of OSP@KH560 at 30% leads to a crystallinity of 45.78% in the composites, which is 35.65% lower than that of PBS, indicating that OSP@KH560 promotes heterogeneous nucleation and accelerates the crystallization rate of PBS, thus reducing its crystallinity. This work provides a new option to prepare PBS composites with good performance and high-cost competitiveness, and further utilizes marine resources while breaking away from dependence on oil resources.