Abstract: Based on the principle of triboelectric nanogenerator and electromagnetic induction power generation, using magnetic liquid as friction layer and magnet at the same time, a magnetic liquid triboelectric- electromagnetic composite energy harvester is proposed in this paper, which can convert low-frequency vibration energy into electric energy and output it. The dynamic characteristics and electromechanical coupling mechanism of different working modules of the compound vibration energy collection system under the action of magnetic field are theoretically analyzed. With the help of finite element simulation software, the multi-field coupling simulation model of magnetic field, electric field, fluid field, and output electromotive force of the compound energy collection system is established. The experimental test platform of compound energy collection system under low-frequency sinusoidal excitation is designed, and the influence of external excitation and external magnetic field intensity on the output characteristics of electric energy is explored. The experimental results show that the designed magnetic liquid triboelectric-electromagnetic composite energy harvester can effectively convert vibration energy into electric energy in low frequency environment.