Supply chain concept has been developed and has attracted the attention of many researchers over the recent decades. One of the most important supply chain management problems is integrated supply chain design problem which has been proposed articles and several approaches in this field. In this research has been studied integrated design of multi-product four levels supply chain problem considering with capacity levels to manufacturing plants and distribution centers whose purpose is to determine the number and location of manufacturing plants and distribution centers, the appropriate capacity level for manufacturing plants and distribution centers, selection of traortation mode due to initial material transmission and product, between different supply chain levels and allocation of customer's demand to distribution centers so that total supply chain cost is minimized and total demand of distribution centers is met. The costs considered in this issue, include Establishment of facilities cost, Variable cost of production, Inventory holding cost, and lead-time cost. One of the most important features in this problem is considering selectable levels of production plants capacity and distribution centers which make flexibility in determining manufacturing plants and distribution centers dimension. In this research, at first, an integer programming model presented for this problem. Then a Meta heuristic solution method based on Genetic algorithm represented according to problem complexity and finally comparison between results originate from this algorithm and exact solution from GAMS software both side of solution quality and time has shown high efficiency of GA.