In this paper, to improve the compatibility of poly(vinylidene difluoride) (PVDF) with barium titanate (BaTiO 3 ) and the piezoelectric property of wearable piezoelectric nanogenerators (PENGs), fluorinated BaTiO 3 (F-BaTiO 3 ) nanoparticles were prepared by the simple thermal annealing of BaTiO 3 prepolymer with PVDF powder, a modified composite nanofiber was prepared by electrospinning with a dispersed liquid consisting of F-BaTiO 3 nanoparticles and PVDF solution, and a PENG was prepared with the modified composite nanofiber as a piezoelectric functional material. Scanning electron microscopy (SEM) showed that F-BaTiO 3 nanoparticles were more uniformly dispersed in the modified composite nanofiber than BaTiO 3 nanoparticles, the analysis of Fourier infrared (FT-IR) spectroscopy showed that the β-phase content of the modified composite nanofiber compounded with F-BaTiO 3 (F-BaTiO 3 /PVDF nanofiber) was higher than that of the modified composite nanofiber compounded with BaTiO 3 (BaTiO 3 /PVDF nanofiber), and when the dosage of F-BaTiO 3 nanoparticles was 5 wt %, the β-phase content of the modified composite nanofiber reached the maximum value (91%), which was about three times that of BaTiO 3 /PVDF nanofiber. The output voltage of the PENG could reach as high as 1.5 V under an external force of 2N and does not decrease obviously after 300 cycles in a vertical pressing test. Furthermore, PENG was demonstrated to be sensitive to the detection of human motions, for instance, elbow flexion, hand slapping a table, and walking. These results indicated that by BaTiO 3 being fluorinated with PVDF, the dispersity of F-BaTiO 3 in PVDF nanofiber, the β-phase content of F-BaTiO 3 /PVDF nanofiber, and the output voltage of F-BaTiO 3 /PVDF PENG were improved.