Electromagnetic launch uses electromagnetic forces that can accelerate objects to hypervelocity in short time. Also due to the controllability of its muzzle velocity and the extremely high responsiveness of whole system, electromagnetic launch technology is considered as another novel way to achieve tokamak device disruption mitigation. Our team has designed a new generation of electromagnetic pellet injection system(EMI). It is able to achieve high-speed injection of the pellet and soft recycle of the armature by using deceleration electromagnetic force. In this paper, the deceleration performance of the C-shaped armature during the deceleration process is analyzed through simulations. The simulation results show that the electromagnetic force of the C-shaped armature's tail during deceleration causes the contact performance between the armature and the rail to deteriorate, and also the armature muzzle velocity cannot meet the requirements of soft recycle. The results of the launch experiments with different decelerated current amplitudes further veriFy the correctness of the simulation analysis and provide ideas for the next design of armatures suitable for EMI.