The present disclosure discloses a video decoding method and a video decoder. The method includes: parsing coding tree split information to obtain a current node; determining coordinates of an upper-left corner of a region covered by a current quantization group based on a depth N of the current node; obtaining a QP delta of a current CU in the region covered by the current quantization group; and obtaining a reconstructed picture of the current CU based on the QP delta of the current CU.