The embodiment of the invention relates to a coding method and device based on a linear block code, wherein the method comprises the step of: according to a linear grouping code coding matrix (32, 14) and an expandable sequence with a length of 8, coding an input information sequence, and outputting a code stream sequence, wherein the linear grouping code coding matrix (32, 14) comprises any one of coding matrixes shown in a table 1 and a table 2. In the embodiment of the invention, the input information sequence is coded by adopting the coding matrix and the expandable sequence of a linear grouping code to obtain the code stream sequence; and compared with the method for coding the linear grouping code coding matrix, coding performance is improved.