In the scale of nanometer, Quantum-dot Cellular Automata (QCA) is a new technology, which utilizes the QCA cells in order to design and implement logical circuits. QCA makes it possible for us to design in Nano scale. Furthermore, in comparison to CMOS technology, it has highly low consumption power. Thus, in the future, QCA technology will be a powerful rival for VLSI. This paper presents two new and optimized QCA designs for Full adder. In comparison to the previous designs, all of the QCA Full adders presented in this paper are relatively optimized. In addition, they are implemented without any wire crossing. In order to test the proposed QCA Layouts and also display the results of the simulations, QCADesigner software is used