In order to avoid continous occurrence of stealing equipments and forcibly occupying fishing grounds, it is so important to develop position indicating radio beacon system with warning function. The system integrates the fishing sonar and position indicating radio beacon as a whole by means of low power consumption data collection technology and satellite data compression technology together with the combination of audio information extraction and infrared technology. Dependent on cavitation effect of the propeller, noise of the diesel engine would be collected through the underwater microphone. In the preliminary experiment, the signal of diesel noise were collected and saved in the computer, in addition, the engine would be turned off and the underwater noise would be collected. In order to observe spectrum and bands of the noise, the signal of noise would be transformed to digital signal and analysed by fast fourier transform with software program in computer. So that the alarm hardware could be designed which depended on ARM board. In embedded systems, acoustic signals were collected and processed with micro controller, and it could indicate whether there is a diesel boats. As the system integrates satellite positioning, sonar detection, radio communication, satellite communication and anti-theft on equipments, the real time transmission and monitering of fishes information could be achieved, which greatly improves the informatization level and fishing efficiency in China's tuna detection, and promotes the high efficiency of oceanic fishery resources. Experimental results show that the common small hook propeller will radiate noise, and frequency of the sound signal is about 8.5 kHZ when it runs steady.