Abstract: The paper describes the progress of the research work on sodium boiling noisedetection. High frequency and low frequency noise signal analysis system with on-line or off--line signal acquisition and processing were set up. We introduced,developed, improved and designed the signal processing, accident alarming, failurediagnosis and autoregression model analysis computer softwares. Utilizing these hard-ware and software, we detected and analysed the noise signals of sodium andwater boiling. The results show that the amplitude of APSD of noise signals inboiling was obviously larger than that in no boiling. Using distinguishing factor ofautoregression model analysis, we can realise on--line and real--time boiling diagnosisand surveillance.