1. A self-compensation method for decoding the belief-propagation algorithm, comprising the following steps: a first step that uses a min-sum algorithm to derive multiple output values in order to approach the operation result of check nodes of a belief-propagation. a second step that check the present number of iterations of decoding in accordance with a checking rule; and a third step that, if in the second step the present number of iterations of decoding is identified with a to-be-corrected state, then performs a compensation procedure for the multiple output values, wherein the compensation term is dynamically selected in accordance with an input value of the checking nodes of the belief-propagation.