Disclosed in the present invention are a data processing method and a data processing device, which are used to reduce the bit error rate in a wireless communications system and improve the transmission performance of the wireless communications system. The method comprises: mapping L bits to be sent onto L bit positions that are comprised in a modulation symbol, the L bits to be sent comprising at least one bit field, and bits in the bit field having high priority are prioritized for mapping to bit positions of the modulation symbol having a high reliability, wherein said at least one bit field is at least one from among an information bit field, a first validation bit field and a second validation bit field; and outputting the modulation symbol.