In this paper, a modeling about centrifugal compressor axial displacement fault diagnosis is proposed through investigating on the mechanical performance and failure mode of thrust bearing as well as the characteristics of axial displacement fault. In this paper, result of experimental studying of the force-displacement curve of rotor at different speed is presented. Numerical simulation method is used to predict the curve in diagnosis model. By comprising the experimental and numerical result, it can be seen that Finite Element Method(FEM) elastic-perfectly plastic material model can get more precise result than linear elastic model and Computational Fluid Dynamics(CFD) method provide a new insight to investigation the physics based diagnosis method. Result of the paper provides the foundation of axial displacement fault self-recovery.