In order to eliminate inter-code crosstalk caused by non-ideal characteristics of backplane channel during data transmission, a DFE (Decision feedback Equalizer) with gain adaptive function is proposed in this paper. The whole DFE adopts half-rate structure to adapt to the requirements of high-speed transmission. An adaptive feedback loop is introduced to implement S-S LMS, and the tap coefficient is adjusted when the cross-talk size changes, to make the equalization effect better. A dynamic comparator is used to sample the data, introducing the smallest possible delay while completing the correct sampling. For the input signal of 5.4Gbps, the simulation results show that the equalizer realizes the correct recovery of data, the recovered eye image width is 0.91UI, and the two post-standard components are successfully eliminated. DFE can effectively eliminate inter-code crosstalk and achieve a better balance effect.