Abstract: Water-saving irrigation is the key to accelerating agricultural modernization and improving irrigation efficiency. A mixed integer programming model is established for a multi-source irrigation system with the objective of minimizing the cost of system flow distribution and pipe installation, to determine the pipe network topology and connecting pipe sizes, where the distribution of water flow is considered. A hybrid heuristic algorithm is designed to integrate local searching with an accurate algorithm. It coordinates the optimization of the layout and design for pipe networks in two stages. The connections between nodes and connecting pipe diameters are analyzed, while the flow to demand nodes is allocated. Test examples with different scales verifies the effectiveness of the proposed coordinated optimization algorithm in reducing construction cost of a multi-source irrigation system.