A video decoding method includes parsing a bitstream to obtain a split mode to transform units (TUs) in a current coding unit (CU). Each of the TUs has a serial number in a one-to-one correspondence with positions of the TUs in the current CU. A transform coefficient of a luminance transform block of a current TU in the TUs is obtained. A transform type of the luminance transform block of the current TU is obtained based on the split mode and a serial number of the current TU. An inverse transform on the transform coefficient of the luminance transform block of the current TU is performed based on the transform type of the luminance transform block of the current TU to obtain a reconstructed residual of the luminance transform block of the current TU. A reconstructed block of the current CU is obtained based on the reconstructed residual.