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In order to acquire clean energy from the natural environment and supply power to the wireless sensors and communication modules, a vortex-induced vibration self-generating device was designed based on the principle of vortex-induced vibration and resonant acoustic amplification. The device mainly consisted of a cavity, a cylinder, a piezoelectric cantilever composite structure, a base and two Helmholtz resonators. Firstly, mechanical analysis of the piezoelectric cantilever composite structure in the self-generating device was carried out. Secondly, based on the computational fluid dynamics method, the dynamic characteristics of the flow field of self-generating device under different plate lengths were analyzed. And the influence of length of cantilever beam on vortex frequency, lift and drag coefficient was clarified. The finite element software ANSYS was used to simulate the transverse reciprocating vibration of piezoelectric cantilever composite structure to finish the structural design. Finally, the structural dimensions of the Helmholtz resonator on both sides of the device were optimized to make the flow field vortex shedding frequency. And the first-order transverse vibration frequency of piezoelectric cantilever composite structure and the resonant frequency of the resonator was consistent. The experimental results demonstrated that the self-generating device can produce an open-circuit voltage with a peak-to-phase voltage of 6.0V at wind speed of 5m/s, and the above three frequencies were consistent. The experimental results also showed that the speed of 4~6.25m/s was the self-locking wind speed range of the self-generating device. Within the wind speed range, the self-generating device can produce the maximum voltage amplitude. The results of the study provided a reference for the structural design of the vortex-induced vibration self-generating device.