The adoption of equal gain transmission (EGT) in MIMO systems can greatly reduce the computational complexity and the design effort of power amplifier. In a temporally correlated channel environment, the channel varies slowly and so does the corresponding beamforming vector. If the slowly varying channel condition can be taken into consideration while designing the feedback schemes of EGT, the computational complexity and feedback overhead of EGT are expected to be further diminished dramatically. In this paper, we propose a differential feedback scheme (DFS) with two algorithms to further improve the performance in EGT. Simulation results show the advantages of the proposed DFS in terms of the feedback overhead and the system performance.