The ordinary differential equations coupling electromagnetic force of dynamics were established for split Stirling engine. The transient displacement vectors of the two pistons were disposed of feedback vectors in numerical computation models of Matlab/Simulink computing environment. Since the total mass of the working fluid remains constant, the instantaneous cyc-pressure was computated by the characteristic gas equation. The differential pressure vector of the expansion space between the compression space was computated by the flow loss in the regenerator. The instantaneous current of generator winding was computated by the balance equation of motional electromotive force. The displacement wave forms was contrast to the expansion piston and the compression piston. In addition, one of the necessary conditions of steady operation was reduced by oscillation theory for split Stirling engine.