The leakage on four kinds of tubes in the large power station boiler is the main reason for unplanned outage of power units.So how to prevent and control the leakage accident has become an important part of ensuring the safe operation of power grid.Sound spectrum analysis method is the most commonly used detection method.Aiming at the problem that the temperature at the top of the boiler is high

and sometimes the positive pressure produced inside the boiler will make ordinary audio sensors damaged easily.A system of high temperature resistance fiber optic audio sensor and acoustic resonator are designed.The work scope of high sensitivity of fiber optic audio sensor can be determined and the leakage noise signal is doubled through the design of acoustic resonators.The experimental test results show this system can effectively test leakage signal inside the boiler tube

and provide a new idea for leakage detection.