In response to the research demand for the armature-rail contact characteristics of a new aluminum alloy material in the series-enhanced electromagnetic rail launch test, an analytical formula for the armature-rail contact resistance to eliminate the influence of the induced electromotive force is derived. Based on the electromagnetic and kinematic analysis of the electromagnetic launch process, a numerical calculation model for the contact voltage and contact resistance of the armature-rail of an enhanced electromagnetic rail gun was established. The model reveals the correlation between the contact resistance of the armature-rail and physical parameters, such as muzzle voltage, muzzle-induced voltage, rail current, rail mutual inductance gradient, armature speed, and armature displacement. The experiment obtained multiple parameters, such as muzzle voltage, rail current, and armature velocity in the electromagnetic rail launch test, and achieved quantitative calculation of the armature-rail contact voltage and the sliding contact resistance of the series-enhanced electromagnetic rail gun. Based on the summary and research of the waveform change law and test phenomenon of the armature-rail contact resistance data obtained from multiple launches, the contact state between the armature and rail during the actual launch process is analyzed, which provides a necessary means to evaluate the sliding electrical contact characteristics of the electromagnetic rail gun and plays a positive role in guiding the research and design of armature-rail matching optimization mechanism.