Abstract: The high-resolution radar based on large time-bandwidth product signal pulse compression is expected to be the future trend in radar development. Its advantages include improved range resolution, operational range, weak target detection, and multi-target detection. Doppler frequency shifts caused by the relative motion between the target and the radar lead to scale effects in the echo signals. Particularly in scenarios involving large time-bandwidth product signals and high-speed target detection, scale effects can cause gain loss in pulse compression. This paper proposes a method for evaluating the gain loss of pulse compression signals due to scale effects. First, the scale effects present in large time-bandwidth product signals in high-speed target detection scenarios are modeled. The impact of these scale effects on pulse compression processing is analyzed. A loss evaluation factor function, defined as the ratio of the distance the target moves within the signal's time width to the signal’s range resolution, is introduced to describe the method for assessing pulse compression gain loss. Quantitative analyses are performed on two typical pulse compression signals: linear frequency modulation (LFM) and phase coding. Simulation results are provided to validate the correctness of the theoretical analysis.