A data re-transferring method based on bit transformation is disclosed in the present invention. The key point of the method is to exchange the location of each bit constituting data according to selected transformation modes before implementing QAM during each data re-transferring process. The method further comprises: a. presetting the transformation mode representing no bit location transformation at mode 0, modulating and transmitting data with mode 0 during the first data transferring process; b. judging whether it is needed to re-transfer the data after completion of the first data transferring process; if not, going to step a to transfer new data; otherwise, further judging whether all of the selected transformation modes have been used, if not, selecting the next mode in turn, if so, selecting the modes in turn from mode 0 again; and c. exchanging the locations of bits within the symbol according to the selected mode, then modulating and transmitting the processed data. With the method, storage amount can be decreased, balance of reliability of bits within the same data symbol after multiple re-transferring processes can be ensured, in addition, performance of the decoder and reliability of data transmission can be improved.