Disclosed are a decoding method and device for concatenated code, for the decoding of concatenated code composed of low density parity code (LDPC) and Reed-Solomon (RS) code. The method includes carrying out LDPC soft decision iterative decoding on bit de-interleaved data flow, and carrying out check decision on LDPC codeword obtained from decoding by using a check matrix; carrying out de-byte-interleave on an information bit of the LDPC codeword obtained from decoding and converting check information of the LDPC codeword into puncturing information of RS codeword; selecting a decoding mode according to the puncturing information of the RS codeword to carry out RS decoding. By way of the solution of the present invention, the RS decoding performance can be improved without increasing the computation complexity, thus greatly improving the receiving performance of the CMMB terminal as compared to the conventional method.