Abstract: In the operation of electromagnetic propulsion devices, the dynamic change in contact resistance between the armature and the rail significantly impacts the system's performance. To address the limitations of existing studies that primarily rely on the Holm's theory of contact resistance and are based on the static state of the armature, this paper employs finite element analysis and the method of controlled variables to investigate the effects of dynamic contact resistance on the motion and temperature characteristics of electromagnetic propulsion devices under actual propulsion conditions. Firstly, key parameters such as muzzle voltage, current, armature velocity and displacement were obtained through experiments. Subsequently, the acquired signals were processed to denoise via using an improved complete ensemble empirical mode decomposition with adaptive noise (ICEEMDAN) combined with a wavelet thresholding algorithm, thus the dynamic contact resistance under real operating conditions could be calculated. Electromagnetic-thermal coupled finite element models were developed to assess the effects of dynamic contact resistance on the armature motion and temperature characteristics, with and without considering the resistance. Experimental comparisons reveal that dynamic contact resistance significantly influences propulsion device performance. And the impact on motion characteristics increases with the armature displacement. Moreover, the presence of dynamic contact resistance can rapidly increase the surface temperature of the armature, leading to the likelihood of ablation at the tail end, which in turn affects the armature's acceleration performance. This research provides theoretical supports for further analysis of the impact of dynamic contact resistance on electromagnetic propulsion devices under extreme conditions.