In order to eliminate inter-code crosstalk caused by non-ideal characteristics of backplane channel during datatransmission, a Decision Feedback Equalizer (DFE) with gain adaptive function is proposed in the paper. The whole DFE adoptshalf-rate structure to adapt to the requirements of high-speed transmission. An adaptive feedback loop is introduced to implementSingle to Single Least Mean Square Algorithm (S-S LMS), and the tap coefficient is adjusted when the cross-talk size changes, tomake the equalization effect better. A dynamic comparator is used to sample the data, introducing the smallest possible delay whilecompleting the correct sampling. For the input signal of 5.4 Gbps, the simulation results show that the equalizer realizes the correctrecovery of data, the recovered eye image width is 0.91 UI, and the two post-standard components are successfully eliminated. TheDFE power dissipation is only 17.8 mW.