Disclosed are a method and an apparatus for high-speed decoding of a linear code on the basis of a soft decision. The method for high-speed decoding of a linear code on the basis of a soft decision may comprise the steps of: obtaining an alignment signal by aligning received signals in order of magnitude; obtaining a hard decision signal by making a hard decision on the alignment signal; obtaining a higher-level signal corresponding to most reliable bases (MRB) from the hard decision signal; obtaining a permuted and corrected codeword candidate by using an error vector according to a current order and the higher signal; calculating a cost for the current order by using a cost function; determining the permuted and corrected codeword candidate as a permuted and corrected codeword according to a result of comparing the calculated cost and the minimum cost; and determining a predefined high-speed condition.