<p>Improving the piezoelectric and mechanical properties of polymer piezoelectric materials is an urgent research work for their application as piezoelectric materials. Thus, in this work, a new polymer piezoelectric material, esterified lignin-modified polyacrylonitrile (PAN/CEHL-PTMG), is successfully synthesized and the related piezoelectric composite nanofiber membrane is prepared by electrospinning. The structure of the membranes is well characterized by Fourier transform infrared spectrometer (FTIR), X-ray diffractometer (XRD), field emission scanning electron microscopy (SEM). The output voltage can reach as high as 1.47 V (64.63% higher than that of the pure polyacrylonitrile membrane) by optimizing the spinning solution (2% esterified lignin). The results indicated that the piezoelectric property of polyacrylonitrile (PAN) is remarkably improved by the incorporation of esterified lignin (CEHL-PTMG). In addition, a simple energy-conversion performance test is conducted, through which the prepared piezoelectric elements with PAN/CEHL-PTMG show the mechanical movement of the arm and finger. It is verified that the PAN/CEHL-PTMG piezoelectric element can complete the energy conversion well in practical application. The results indicated that an appropriate amount of CEHL-PTMG was conducive to the transformation of the planar sawtooth conformation in the microstructure of the polyacrylonitrile nanofibers. Meanwhile, mechanical tests exhibited that the CEHL-PTMG also could effectively enhance the tensile strength and elongation of the membranes.</p> Graphical abstract <p></p>