Piezoelectric nanofibers have received extensive attention in the field of electronic devices, but they are still restricted for further development, due to their limited dipole arrangement. Herein, we propose spatially confined MXene/polyvinylidene fluoride (PVDF) nanofibers for piezoelectric application, with dual functions of pressure sensing and energy harvesting. The spatial confinement of MXene/PVDF nanofibers can actively induce the optimally aligned –CH2–/–CF2– dipoles of PVDF and dramatically boost spontaneous polarization for piezoelectric enhancement. The voltage and current generated by fabricated MXene/PVDF (0.8 wt%) nanofiber piezoelectric electronic devices are respectively 3.97 times and 10.1 times higher than those generated by pure PVDF nanofibers. Based on these results, the developed bifunctional electronic devices are applied to monitor various human movements and to harvest energy. Notably, the results of this work allow for the development of nanofibers with excellent piezoelectric performance using a spatial confinement mechanism.