Shipboard electric network is an independent mobile electric network with all forms of loads and power transformation devices. This paper proposes the power line carrier (PLC) application to shipboard lighting network in the first place, because lighting network is of less harmonic wave, simple load, accessible pulse noise and widespread distribution. Considering the skin effect, we calculate the lighting cable parameters including AC resistance, AC inductance and line-to-line capacitance. The relation between the frequency and the characteristic impedance and input resistance is deduced according to the Microwave Transmission Theory. And we can realize two kinds of impedance matching between PLC coupling circuit and lighting cable: one is conjugate match in transmitting terminal, which can achieve maximum transmitted power; the other is impedance match in loading terminal, which can achieve maximum received power. At the same time, we give the parameter design of the coupling circuit suitable for shipboard electric network.