The invention provides a polarization code decoding method. On the basis of the polarization code SC decoding method, the calculation of an f function node is simplified, a hyperbolic tangent functionand its inverse function operation are replaced by a polyline approximation function, and the polyline approximation function only requires addition and multiplication. The polarization code decodingmethod has the beneficial effects of greatly reducing the computational complexity, greatly saving the memory resource compared with the table lookup method reducing the hardware cost, and solving the problem that the polarization code has a high complexity in the log likelihood ratio domain decoding operation.