This paper discusses the channel gain characteristics of a two-conductor power-line communication system under a given transient analytical model. The channel frequency responses are derived with different transmission-line lengths and terminal loads. Compared with previous works on power-line communication, the transient model can more accurately describe the variation of the channel frequency responses, especially when transients occur on the transmission line. Simulation results show higher accuracy is achieved compared with the results under the traditional lumped-circuit π model.