In this paper, the authors are implemented BPSK modulation technique, a subsystem module of digital communication using reversible logic. Later on they have implemented a QPSK modulation technique using reversible logic and the QPSK modulator unit will be modelled using HDL code and simulation will be done by ModelSim 6.0 simulator to verify their functionality in the system. The digital system of QPSK is designed using a reversible logic gates which yields in low power, less required area and less amount of delay. Reversible logic is mainly used to construct low power circuits and also used in quantum computing, optical computing and DNA computing to produce zero power dissipation.