Abstract: Aiming at the problem that the current single electromagnetic field cannot reflect the deformation of the key parts during the breaking process of the electromagnetic repulsion mechanism, this paper proposes a collaborative simulation method of the electromagnetic field, the structural analysis field and the transient force field. The parameters of radial turns and the size of the core connection components are used to study the stress and deformation of multi-field co-simulation for fast switches. Secondly, aiming at the problem that the DC circuit breaker needs a fast switch to provide a higher closing holding force under the condition of a larger rated working current, the effect of the T-shaped armature structure on the closing holding force is simulated, and its influence on the deformation and stress of the repulsive coil shell during the opening process is explored. Finally, based on the multi-field collaborative simulation results, a hybrid dual-coil type rapid electromagnetic repulsion mechanism is designed. The results show that the repulsion coil with moderate thickness and Q235 material has less stress and deformation and faster opening speed; the central support rod and the repulsion coil size have a mutually affecting relationship; the increase in the width and thickness of the T-shaped armature steps keeps the increasing rates of the closing holding force first fast and then slow. Under the same circuit parameters, the increase of the closing holding force reduces the opening speed but the deformation and stress decrease, and there is a critical optimal situation for their mutual restraint. In this paper, the study of stress and deformation through multiphysics co-simulation provides theoretical guidance for the rapid switch design and optimization, and also provides a certain technical reference for engineering applications.