The self-excitation of the spring clutch is realized through the pre-compression between the excitation coils at either end of the spring and housing to generate frictional torque to energize the spring.The pre-compression amount of excitation coils at either end of the spring has a great impact on the binding property and lifetime of spring clutch.The spring clutch dynamics model is established by using the finite element analysis method.On ABAQUS platform,the speed synchronization of high speed spring clutch output shell and the input shell,the Mises stress and radial displacement of spring under different pre-compression are solved,and then the pre-compression amount condition of the self-exciting meshing of the spring clutch is obtained,and it is compared with the critical amount of pre-compression of clutch obtained by the analytic solution.Besides,the finite element analysis results show that the steady state stress distribution of spring exhibits M shape,that is,the transition coils have peak stress while the middle coils have uniform stress distribution.The basis for optimal design of spring clutch can be provided.