Polyvinyl chloride plasticized by diethyl adipate (PVC/DEA) films were fabricated by using solution casting method. After thermal poling, the piezoelectric coefficient (d33) of the PVC/DEA film was investigated. The result showed that the d33 of the PVC/DEA film first increased and then decreased with the increase of the DEA content, and reached a maximum of 28 pC/N at a loading fraction of 6 wt% DEA, which was more than four times that of the neat PVC film. The enhancement in the piezoelectricity can be correlated well with the changes in the mechanical and dielectric properties of the PVC/DEA films upon the incorporation of DEA. In addition, the PVC/DEA based piezoelectric device showed a superior output performance with an open-circuit voltage (Voc) of 2.4 V and a short-circuit current (Isc) of 60 nA, which even outperformed over the commercial piezoelectric PVDF under the same periodic external force. More importantly, such piezoelectric device demonstrated excellent durability over a thousand of mechanical compression. This work provides a novel strategy for designing high-performance piezoelectric materials applied as sensors or nanogenerators.