Abstract Polymer melt blending has become a main and important method to modify polymer materials for overcoming defects and obtaining excellent performance. The mechanical properties, compatibility, tribological properties and modification mechanisms of polyphenylene sulfide (PPS) alloys have been investigated over the last decades. However, there are few researches on PPS/polyvinylidene fluoride (PVDF) alloys, and material researchers have paid little attention to the manufacture and properties of PPS/PVDF alloys. In our research, the morphology, thermal properties and mechanical properties of PPS/PVDF alloys were first studied. PPS/PVDF alloys were prepared by a simple polymer melt blending. Fourier transform infrared spectrometer (FT-IR), X-ray diffraction (XRD) and scanning electron microscope (SEM) were used to characterize the morphology of PPS/PVDF alloys. It was found that the PPS/PVDF alloys had a “sea-island” structure with a poor adhesion at the interface between the PVDF phase and PPS matrix. The addition of PPS may also promote the transformation of α-phase to β-phase in PVDF. The thermal properties of PPS/PVDF alloys were confirmed by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). It indicated the addition of PVDF would accelerate the crystallization of PPS and increase the crystal perfection of PPS. It was clearly that the thermal stability of PPS/PVDF alloys could be improved by the addition of PVDF especially when the PVDF content is lower than 20 wt %. When the content of PVDF was only 5 wt %, the tensile strength and tensile modulus of PPS/PVDF alloys had a significant improvement compared with pure PPS. Furthermore, it was also found that the addition of PVDF could also increase breaking elongation rate in a small degree.