Triboelectric nanogenerators (TENGs) have received much attention as cost-effective and friendly energy-harvesting devices that effectively convert mechanical energy from the environment into electrical energy. In this study, a naturally degradable TENG was papered based on TiO2/CMC, which is a cellulose derivative with ease of degradation, good biocompatibility, and low cost. By doping TiO2 nanoparticles, the open circuit voltage, short circuit current, and transfer charge were significantly improved compared to the TENG-based pure CMC film because of the increased dielectric constant, and the corresponding values of 121 V, 6.7 μA, and 20.5 nC were obtained at a doping concentration of 8 wt %. Then, the manufactured triboelectric nanogenerator (MT-TENG) was successful in lighting up LED lights and powering commercial calculators. Moreover, the MT-TENG was used to collect human mechanical energy, which confirms its potential applications. This study provides a feasible path for the research of TENGs based on biomass materials.