The spatiotemporal coupling (STCs) distortion of large aperture ultra-high peak power laser will degrade the pulsed beam in both near- and far-fields. To accurately predict the light field distribution at the focus and compensate the spatiotemporal coupling distortion, a single-frame measurement of full three-dimensional spatiotemporal coupling distortion based on frequency domain separate spatial-spectral interference is proposed. The setup requires only a slit array attached in front of an Imaging Spectroradiometer. The whole procedure of carrier frequency distinguished spectral interference measurement is simulated in this study, simulation results prove the correctness and effectiveness of the presented measuring method. The effectiveness of this method will be further verified by experiments in next step.