Abstract: The finite element simulation model for inclined strut of a conveyor is built by CAE tool, then the design of experiment and response surface method are introduced to fit response surface model for fatigue life of inclined strut. On this basis, considering the effect of random factors such as dimension, load and material performance etc., the reliable life prediction problem can be solved by using performance measure approach, and then the reliable life and sensitivity degree can be gotten directly. Finally, the structure of inclined strut is improved by using sensitivity degree, the reliable life of new structure is longer than before.