Poly(butylene succinate) (PBS) composites containing 10 wt% amorphous-Si 3 N 4 , α-Si 3 N 4 and β-Si 3 N 4 were prepared by melting mixing. The effect of Si 3 N 4 phase structure on the crystallization and melting behavior of PBS was investigated by Differential Scanning Calorimetry (DSC) and Wide-Angle X-ray Diffraction (WAXD). The non-isothermal crystallization kinetics of PBS and PBS/Si 3 N 4 composites was studied by Jeziorny methods. The crystallization activation energy and nucleation activity of PBS and PBS/Si 3 N 4 composites were calculated according to Friedman and Dobreva methods, respectively. The results show that Si 3 N 4 particles have obvious heterogeneous nucleation for PBS crystallization, increasing the crystallization temperature and reducing the crystallization activation energy. Among those Si 3 N 4 particles studied, α-Si 3 N 4 particles have the strongest heterogeneous nucleation for PBS crystallization, which indicate that the phase structure of Si 3 N 4 particle have great influence on the crystallization behavior of PBS.