Taking network conversion value of annual cost as the weight of pipe segment to establish objective function, and using the method of line-up competition which based on breaking circle and Mayeda-Seshu algorithm as solving method,the paper used this new method to optimize tree water pipe network and applied it in a case study.The result showed that the algorithm can not only completely avoid the drawbacks of producing infeasible solution in the evolutionary process by conventional optimization algorithm, but also inherit the advantages of line-up competition algorithm.The method can improve the efficiency of the algorithm significantly and ensure the accuracy of calculation results. The optimization algorithm the paper proposed has great significance for the optimization design of layout form of tree water pipe network.