Abstract: Pivot is one of the key elements of some highly precise devices used in the fields of aviation and aerospace etc. The torsional stiffnesses versus torsional angles and the corresponging deformation of the pivot under torsion are very important behaviors that must be controlled when the pivot is in use. If the behaviors do not satisfy the requirment,the whole device will be out of action. To date,these kinds of products still rely on import. Employing the MFGS method geometric nonlinear part and linear part of MFEP software, whose calculating of capabilities are the same as those of ADINA software, we calculated these above mentioned behavior of related pivot specimen. The analysis shows that the actual welding depth between the rotating sleeve and flat crossed spring will affect the calculation results to a great extent. Also, the effect caused by the original wrinkle and the thickness tolerance of the flat crossed spring, and the changes of constrained conditions of a sleeve on the torsional stiffness of the pivot were observed. At last, the paper proposed some suggestions for further research and manufacture of the pivot.