A decoding method and device are provided. The method includes: decoding grouped original data in parallel by a first decoding unit to obtain grouped decoded data; decoding merged grouped decoded data by a second decoding unit to obtain decoded data; and if the sum of the lengths of the decoded data is an integer multiple of an upper limit of the decoding times of the second decoding unit, updating the first decoding unit and the second decoding unit, and if the sum of the lengths of the decoded data is not an integer multiple of the upper limit of the decoding times of the second decoding unit, updating the second decoding unit to obtain the decoded data again, until the sum of the lengths of the decoded data is equal to a decoding length, and merging the decoded data to serve as a decoding result of the original data.