Tools of tunnel boring machine CAD models have been built by CAD software, it is analyzed static characteristics and fatigue characteristics by finite element analysis and obtaining the displacement in the poor stiffness conditions. Improving its structure to strengthen stiffness and fatigue life by the calculate result. The final result shows that the structure can satisfy its rigid command and can fit the soil conditions above 5%-10%. Damage frequency of tools is greatly deduced. It provides a theoretical basis for the actual design and product manufacturing.