Miscibility and crystallization behaviors of poly(ethylene succinate)/poly(p-dioxanone) (PES/PPDO) blends were investigated by differential scanning calorimetry (DSC), polarized optical microscopy (POM), and wide-angle X-ray diffraction (WAXD). PES/PPDO blends are completely miscible as proved by the single grass transition temperature (T-g) dependence of composition and decreasing crystallization temperature of the blends in comparison with the respective component. POM observation suggests that simultaneous crystallization of PES and PPDO components in the blends took place, spherulites of one component can crystallize inside the spherulites of the other component, and the unique interpenetrated crystalline morphology has been formed for the blends in the full composition range. Isothermal crystallization kinetics of the blends was studied by DSC and the data were analyzed by the Avrami equation. The results suggest that the crystallization mechanisms of the blends were unchanged but the overall crystallization rates were slowed down compared with neat PES and neat PPDO. WAXD results indicate that the crystal structures of PES and PPDO did not change in the blends.