Abstract: To solve the time-based distortion correction of high-speed sampling oscilloscopes with the bandwidth of more than 10 GHz, and to increase the measurement accuracy, the selection of phase of input signal, group of signals and selection of harmonic order number are simulated by referring the time-based distortion model on the basis of least squares method. The error of time-based distortion is minimum when input signals' phases are orthogonal, the group of signals is four, and the harmonic order number is three. The conclusions were applied to the time-based distortion correction algorithm, and smooth waveform curve was simulated.Results show that compared with the original waveform, the time-based distortion correction algorithm corrects the system error caused by time base distortion, verifies the correction of the conclusions and validity of the time-based distortion correction algorithm.