High-speed A/D converters are important components in equipment, and their working environment is deteriorating with the continuous increase in device conversion clock frequency. Accurately testing the time parameters is particularly essential for comprehensively evaluating the performance of A/D converters. Currently, the time parameters for high-speed A/D converters are primarily tested by directly testing the output through an oscilloscope with a high sampling speed. In this study, the time-domain reconstruction of high-speed A/D converters is proposed. It can be used to test the time parameters of high-speed A/D converters through computer digital signal processing and avoid dependence on the sampling speed of oscilloscopes. Moreover, by studying the time-domain reconstruction of high-speed A/D converters and its application, this study verifies the correctness of the principle through experiments.