Abstract: The crane is a key equipment for an ocean drilling platform. To ensure the safe operation of the entire system, it is necessary to study the structural mechanical property of the truss boom in the hoisting plane. With consideration of such uncertain factors as the structural features of the truss boom and the component performance degradation, a three-dimensional numerical model of the boom is built using the finite element method, in which, the stresses of the main load-bearing member bars are taken as the key indicators and the relevant design parameters as the input updating objects. Numerical simulations and experiments on the whole hoisting process are carried out. It is indicated that the method can simulate the hoisting process and the structural mechanical property, the failure shape and the dangerous position can be obtained. This method provides some insight for the lifting task and the security operation of the jib structure, and is suitable for engineering applications.