To facilitate the construction and optimization of mobile microwave relay network, a method of mobile microwave relay network construction based on the double coding genetic algorithm(DMGA) is proposed. Taking the maximization of network value as the optimization goal, considering the node value, attraction coefficient and fading probability, the intelligent distribution of relay device for each node is realized. By studying the non-linear relationship between the network value and the number of devices, the concept of optimal configuration points is introduced, which provides a quantitative basis for the allocation of microwave relay devices. In the genetic algorithm, the double coding strategy of the adjacency matrix and the adjacency list is used. The advantage of the adjacency matrix is that the change of gene will not produce repeated and self-loop links, and the advantage of the adjacency list is that the change of gene will not affect the total number of links. The two coding strategies are alternately used in mutation and cross operation, which makes the constraint condition and chromosome morphological characteristics match. This coding method avoids the iterative operation which is used to meet the constraints, and improves the operation efficiency. The simulation results show that compared with the single coding, the proposed double coding strategy reduces the computation time greatly.