In our natural environment, mechanical energy has the advantages of universality, diversity, no pollution and easy collection, and occupies a place in various forms of energy. The use of piezoelectric nanogenerators to collect this mechanical energy can provide a feasible solution for the power supply of intelligent functional electronic devices. A BaTiO3/PDMS and BaTiO3/PDMS/C based composite nanogenerator was prepared with lead-free barium titanate (BaTiO3) nanoparticles, carbon nanotubes, and polydimethylsiloxane (PDMS). The results show that the output signal of BaTiO3/PDMS based composite nanogenerator firstly increases, and then decreases with increasing BaTiO3 content. The optimal output signal is obtained at BaTiO3 content of 12%, and the output current and output voltage are 42 nA and 18 V, respectively. The output signal of BaTiO3/PDMS based composite nanogenerator is further improved with introducing C nanotubes. The BaTiO3/PDMS/C based piezoelectric nanogenerator has the optimal output signal when the content of C nanotubes is 2%, and the output current and output voltage are 73 nA and 19 V, respectively. The results indicate that BaTiO3/PDMS/C based piezoelectric nanogenerator has a great application potential in self-powered microelectronic wearable devices.