Abstract: Comprehensive inference base is a core of on line monitoring and feedback analysis system of safety monitoring for Shuikou Hydropower Project.It relates to the realization of the function objects of the system.Through systematically studying inference flow chart and inference models of the system,the design and implementation of the comprehensive inference are investigated in detail.On the basis of the thought of modularization design,following the principle that the key problems must be resolved emphatically with overall consideration of all problems and adopting a clear and reasonable inference flow chart,the comprehensive inference base capable of finding quickly doubtful points of measured data,analyzing their geneses in real time and judging correctly the character and status of dam safety,is worked out.The trial operation results show that the design of comprehesive inference base is reasonable,function complete and operation simple;it can provide technique support for monitoring online and comprehensive assessment of the safety status of dam.