Abstarct: Due to the reduction of electronic devices scale into Nano and necessity use of molecular systems in the electronic devices, in this dissertation calculation of electronic charges is presented. These models are basic models of nano devices in some groups of organic molecules. By considering the importance of carbon and hydrogen in molecular electronics industry, three groups of hydrocarbons have been selected to calculate electrical charge distributions. These molecular groups are considering in different atomic bond structures such as Alkans, Alkadeines and Deallys which are different in bond structure. By decreasing dimension of devices in molecular scale, movement of each electron has great influence on the operation of system. On the other hand, electrical properties of molecular systems are different in neutral state and charged state, so calculation of electrical charge distribution plays important role in recognizing behavior of nano devices. The electronegativity equalization method is employed for calculating electrical charge distributions. This is a semi empirical method and should be calibrated by computational method. So first of all, charge distributions are calculated by electronegativity equalization method in genetic algorithm then results are calibrated with accurate method named by density functional theory. Results show that least squares error of electrical charges in neutral state for both methods of Alkans, Alkadeines and Deallys, are 0.537, 0.365 and 2.336 respectively. In charged state these quantities increase to 8.177, 2.653 and 3.616. To make conclusion from experimental results electronegativity equalization method have high accuracy in neutral state but the accuracy of method decreases in charged state.