A decoding apparatus and method in a BWA communication system are provided, in which an ID-based decoder controller detects an ID from a data block by partially decoding the data block, and if the ID indicates that the data block is not for the receiver, outputs a control signal commanding non-decoding for the data block, a bitmap table controller indicates the data block as a non-decoding data block in a bitmap table according to the control signal, and a decoder distinguishes data blocks to be decoded from non-decoding data blocks based on the bitmap table, decodes the data blocks to be decoded and outputs the decoded data blocks, and simply outputs the non-decoding data blocks without decoding.