The embodiment of the invention discloses a data transmission method, which is used for adaptively regulating transmission modes of data units according to conditions of full-bandwidth transmission channels in case of failure of the full-bandwidth transmission channels. The method comprises the following steps: detecting full-bandwidth transmission channels of a bus; if certain full-bandwidth transmission channels fail and the number of the failing full-bandwidth transmission channels is less than or equal to M, selecting N full-bandwidth transmission channels from the full-bandwidth transmission channels which do not break down for the transmission of the data units; if certain full-bandwidth transmission channels fail and the number of the failing full-bandwidth transmission channels is greater than M, performing reconfiguration of the data units according to the number of the full-bandwidth transmission channels which do not break down and the target beat number.