This paper mainly explores structure health monitoring decision-making theory and method of in-service hoisting machinery.It discusses the selective basis of indexes on structure health monitoring,determination method of each monitoring point which corresponds to the index,and selection and layout principle of corresponding sensors.On the idea of set theory,this paper also explores three different kinds of analysis decision model,which separately base on simulated analysis,damage data and Delphi method.Thus,different decision models are selected according to the abundance of materials acquired in practice to assure the accuracy of analysis results and also avoid interaction of different structures in the same level.At last,taking a gantry crane as an example,this paper shortly introduces crack decision model analysis and operation processes on simulation analysis.