Quantum-dot cellular automata (QCA) is one of the promising budding technologies which is able to properly replace the old semiconductor transistor technology at the Nano scale level. It is attractive for its size, fast speed, feature, very scalable, high frequency switching and low power consumption compared to CMOS technology. In the near future the QCA may take over CMOS because of its significant benefits. This paper is discusses the implementation and simulation of the results of various logic gates using quantum dot cellular automata (QCA). Continued intricate designs can be made using these designs methods.