Channel interpolation methods based on zero-padding DFT for OFDM systems were investigated. Two conventional interpolation schemes for channel estimation were analyzed. Analysis shows that the two methods are equivalent, and zero padding can be used to reconstruct the channel impulse response samples of length N, where N is the number of total subcarriers. The reconstruction error of conventional zero-padding methods was discussed, and a new zero-padding method was proposed. Simulation results show that the above analysis is correct, and the reconstruction error of channel impulse response is decreased by the proposed method in some channel conditions. Furthermore, the channel interpolation with the proposed zero-padding method is robust to the distribution of path delay, and the performance of system is enhanced.