The key technology of the operational monitoring and pre-alarm technique for hydropower plant pressure pipe is researched in this paper. The running characteristic parameters of the pressure pipe is proposed

the alarm rules for those parameters is formulated and the pressure pipe evaluation system based on D- S evidence theory is proposed

which can evaluate pressure pipe running status as dangerous

abnormal

normal states. Through this system

the plant management can make a more reasonable maintenance plan

to avoid blind investment and achieve disaster prevention and mitigation targets.