The pyrolysis characteristic of polyvinylidene fluoride (PVDF) with and without pine sawdust (PSD) were investigated using thermogravimetric analyzer coupled with Fourier transform infrared and mass spectrometry (TG-FTIR-MS). The synergistic effect of PSD and PVDF were found. The Kissinger-Akahira-Sunose (KAS) method was used to analyze the kinetic characteristics. Compared with pure PVDF and PSD, the activation energy range of the mixture changed dramatically. The structures of gas-phase components obtained from co-pyrolysis were characterized by FTIR and MS. And the co-pyrolysis reaction mechanism of PVDF and PSD was discussed. The ion current change showed that obvious interaction appeared between PVDF and PSD. The introduction of PSD can facilitate the pyrolysis of the PVDF. The strongest interaction took place at 1:3 mass ratio of PSD and PVDF. The barrier effect of PVDF was used to explain the involved reaction mechanism. The drawback was notable when ΔW method was used to describe synergistic effect of PSD and PVDF mixture. The involved mechanism was proposed in this paper.