Embodiments of the present disclosure provide a decoding method of a polar code, including: acquiring a receiving sequence and a check matrix, wherein the receiving sequence is output on a channel after an input mapping sequence is encoded; carrying out Trellis path search according to the receiving sequence and the check matrix, and calculating Trellis path likelihood information corresponding to the input mapping sequence; calculating a decision value corresponding to the input mapping sequence according to the Trellis path likelihood information; and de-mapping the calculated decision value corresponding to the input mapping sequence according to a preset mapping relation to obtain a decoding sequence. The input mapping sequence belongs to a finite field GF(q), when decoding the polar code, the Trellis path search is carried out, and the decision value is calculated and de-mapped to simultaneously reduce a maximum list value and greatly reduce an average list value.