In order to address the problem that it is difficult to maintain the power supply of low-power wireless sensor nodes in remote areas and special scenarios, this work investigates a fluid kinetic energy harvesting technology based on flow-induced oscillation phenomenon, which can realize the conversion process from fluid kinetic energy to electric energy by combining with piezoelectric technology. Through numerical simulation and experimental research on the phenomenon of flow-induced oscillation, the flow field and sound field distribution characteristics in the cavity structure are analyzed, and the influence of fluid velocity on the frequency and amplitude of acoustic oscillation is explored. The acoustic-electric conversion process is simulated by COMSOL software, and the complete conversion process of fluid kinetic energy to electric energy is realized. The research results show that there exists an acoustic oscillation range with stable frequency under certain speed conditions, which can drive the piezoelectric transducer to output a voltage with stable frequency. When the gas flow rate is 30.5 m/s (equivalent to the flow rate range of high-pressure gas transmission pipeline), the amplitude of the sound field pressure can reach 6.12 kPa, corresponding to an output open circuit voltage of 2.62 V. When an external 15 kΩ resistor is connected, the maximum output power is up to 0.29 mW.