Abstract: To improve the health detection efficiency and accuracy of large and complex equipment structure, a design of an acoustic emission sensing unit with wireless transmission function was proposed in this paper. The hardware of the sensing unit included measurement sensors, calibration sensors and circuit boards, etc. And the functions of wireless networking, signal automatic acquisition and real-time transmission were realized by the upper computer software. In addition, its wireless transmission distance and detection sensitivity were tested. The results show that the sensing unit can achieve stable data transmission at a distance of 40 m under the cover of 24 cm thick cement wall or 80 m in an open environment. The wireless networking signal synchronization accuracy is better than 10 μs. It can detect a leakage rate of 0.286 m³/h within a range of 8 meters in carbon steel plate. The proposed design method may provide a reference for the application of acoustic emission detection engineering in large-scale equipment.