Abstarct: While prevalent scaling of CMOS technology faces physical limitations, QCA technology, which promises implementation on molecular scale, operating at room temperature and working at high speeds, is an important and serious alternative. In this thesis, we have studied the edge effect related to the electric field of input electrodes on a molecular QCA wire that is responsible for transmitting information from the electrodes to the QCA circuit. Electrodes and wire are located on the substrate Si/SiO2 and the geometric details and dielectric properties of all components of the input structure are included in the simulation of the edge effect. The first cell of the wire is affected by the electric field of the gap of the electrodes and transfers the polarization to the other cells of the wire. Due to the edge effect of the electrodes, the polarization of other cells is affected by the electric field and the possibility of error increases. In this thesis, the electric field of the electrodes is calculated within electrodes’ voltage sweep from 0 to 1.5 V. This study shows that the edge effect increases with a particular ratio, while the electrodes’ voltage increases. The results of the simulation of the edge electric field was imported in the molecular QCA wire model. In this model, the effects of external electric field and neighbor cells and also tun- neling energy are included for each cell. In addition to, we considered the entanglement between single electron cells in this model. All cells’ polarizations, kink energies and uncertainties are calculated using quantum mechanics rules. The results of applying the electric field with edge effect are compared with the edgeless condition that is ideal condition in which the electric field of the electrodes interacts with only one molecule. The research shows that the selection of large electrodes for the QCA input system leads to a sharp drop in the polarization of cells whose sign is opposite to the direction of the electric field. In addition to, choosing molecules whose tunneling energies are between 50 and 100 meV to have acceptable polarization and stable wire, at the same time.