In this paper, a Genetic Algorithm (GA) optimization technique proposed to find optimal sizing and location of multi distributed generations in electrical networks. The objective function based on a linearised model to calculate the real power losses as a function of power generators. This method based fundamentally on a strong coupling between active power and power flow both as function voltage angles. The using of multi Distributed Generation (DG) units has been addressed to minimize the objective function (real power loss) taking into account DG capacity, transmission line capacity and voltage profile constraints. In order to demonstrate the effectiveness of the proposed method, it is applied on (14, 30 and 57) IEEE standard systems by set maximum and minimum capacity of multi DG units based on the type of renewable energy resources. Results show that the linear model combined with GA is efficient in reducing real power losses by finding the optimal location and size of DG units.