In order to analyze the effect of armature′s velocity and quality changing on the accumulated thermal energy of rail, the thermal field model of rail was established and the rail temperature variation was calculated. Compared with the experimental results measured by FBG (fiber Bragg grating) temperature sensors, the correctness of the model and the measurement results were verified. On this basis, three types of experiments were designed to analyze the differences accumulated from the thermal energy on rail under different velocity, quality and the same energy level in different velocity. Experimental conclusions can provide valid references for determining the interval between two launches and designing the cooling system.