A single-shot fourth-order autocorrelator based on cross-polarized wave generation (XPW) is proposed for the temporal contrast measurement, where the XPW process has the advantages of higher energy conversion efficiency, more compact setup, and less sensitivity to misalignment in comparison to the self-diffraction process. The measurement dynamic of 1012 is obtained with only 6 mJ input laser pulse, where the input beam for XPW is focused by a cylindrical lens and XPW signal with the energy of 400 µJ and time duration of 27.2 fs is obtained. Furthermore, beta-barium borate crystal with the thickness of 6 mm and cutting angle of 56° is used for the sum-frequency generation process to benefit the correlation efficiency. The compact setup could help explore the temporal contrast property of the high-power laser pulse.