Disclosed herein is a video decoding method including determining a zero-out width threshold and a zero-out height threshold for distinguishing between a transform coefficient coding region and a zero-out region of a current block according to a size of the current block, determining the transform coefficient coding region and the zero-out region of the current block according to the zero-out width threshold and the zero-out height threshold, acquiring transform coefficient information of the transform coefficient coding region from a bitstream and determining a level of a transform coefficient of the transform coefficient coding region according to the transform coefficient information, determining a level of a transform coefficient of the zero-out region as 0 without acquiring transform coefficient information, and reconstructing the current block by inversely transforming the transform coefficient of the current block.