A communication method includes obtaining a plurality of to-be-encoded symbols; determining, from a symbol matrix, a plurality of first symbols corresponding to the to-be-encoded symbols, where the symbol matrix includes a plurality of rows of symbols and a plurality of columns of symbols, symbols in the symbol matrix constitute a plurality of blocks, the blocks constitute a block matrix, and the first symbols include symbols in a plurality of first blocks in the block matrix, where the first blocks are grouped into at least one block group, a difference between row numbers of any two first blocks in any block group is not the same as a difference between row numbers of other two first blocks in the any block group; and performing check processing on the first symbols and the to-be-encoded symbols to generate checked symbols.