Physical and mechanical parameters of hydraulic structure under complex operation conditions tend to vary with the growth of time, and it is important to obtain these parameters in time for mastering working state, and guiding safety monitoring of hydraulic structures. In this paper, on the basis of quantum genetic algorithm (QGA) and finite element model, we establish an inverse model for mechanical parameters of dam. Through coding by using MATLAB, we build the interface of command calling for finite element software, and establish objective fitness function in association with calculated data of finite element model and measured data. Structural parameter inversion of hydraulic building is completed by intelligent optimization of QGA. In order to verify the algorithm in this paper, we take a concrete gravity dam as an example to carry out inverse analysis of comprehensive elastic modulus for dam concrete and rock in the foundation. Results show that the inversion accuracy and computing speed of the method above are better than those of traditional genetic algorithm. Finally, the research can be referenced for similar projects.