Most of the researches about frequency domain equalization assume that the single carrier wireless communication system works over static channels. However, with more and more requests for mobile wireless reception, we have to consider the case of time-varying channels. In this paper, we propose a frequency domain feed-forward filter combined decision feedback equalizer over time-varying channels (FD-DFE-TV) for single carrier systems. Moreover, some complexity reducing techniques are provided to lower the additional computational burden brought by the disposal in time-varying channels. Simulations show that the proposed method can effectively lower the system error floor thus has superior performance than existing FD-DFE structure in time-varying environment, especially in high speed mobile reception.