A decoding method is provided. The method includes: parsing a bitstream to obtain a syntax element, where the syntax element includes at least an index of optimal candidate motion information of a current block (s151); determining, based on the syntax element, to construct a first list or a second list for the current block (s152), where the first list is a block-based candidate motion information list, and the second list is a subblock-based candidate motion information list; determining optimal motion information from the first list or the second list based on the index (s153); and predicting the current block based on the optimal motion information (s154). In this method, the block (BLOCK)-based candidate motion information list and the subblock (SUB-BLOCK)-based candidate motion information list are distinguished from each other. This effectively reduces transmission costs of the optimal candidate motion information.