Abstract: Triboelectric nanogenerator (TENG) technology is a kind of energy harvesting technology based on materials with different electronegativity, which realizes charge transfer between materials through the coupling effect of electrostatic induction and triboelectric, so as to convert environmental energy into electric energy. Due to its huge application potential in the fields of the Internet of Things and its related smart industries and new energy, the TENG technology has received great attention and become a research hotspot at home and abroad since it was proposed. The nonlinear mechanical mechanism is extended to the TENG, which has complex nonlinear dynamic behavior under the excitation of low frequency environment and can generate large dynamic response, and then efficiently convert the low frequency environmental energy into electric energy. In this paper, the principle of energy harvesting by TENG (e.g., the sliding-mode TENG and the contact-separation mode TENG) and the basic working principle of nonlinear TENG are briefly introduced. Then, the research work of energy harvesting by nonlinear TENG is summarized in detail from three aspects: bistable TENG, multistable TENG and quasi-zero-stiffness TENG, etc., that are employed to harvest low-frequency ambient energy. Moreover, the fundamental principle of these nonlinear TENGs and the typical researches are reviewed as well. Meanwhile, it can be clearly seen that the frequency band of the energy harvesting of the nonlinear TENG is narrow, and the electrical output of the nonlinear TENG should be further improved. To address these issues, the researchers have proposed a lot of methods to improve the electrical performance of the nonlinear TENG. The performance improvement strategy of the nonlinear TENG is described in detail from two aspects, such as impact-mode TENG and hybrid TENG. Finally, this paper summarizes the research progress of nonlinear TENG, analyzes the shortcomings of current research, and prospects the future research direction of nonlinear TENG technology.