A self-compensation method includes: firstly using a min-sum algorithm to derive multiple output values in order to approach a operational result of the checking side of a belief-propagation; and then checking the present iteration number of decoding based on a checking rule; and finally, if in the previous step the present iteration number is identified with a to-be-corrected state, then performing a compensation procedure on 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. The invention also provides an automatic compensation apparatus, which consists of devices such as a min-sum operating unit, and a dynamic quantization control unit, etc., which can be used, while executing the invented method described above, to decode the belief-propagation algorithm.