In order to improve the construction of the assembly center, this paper builds an assembly center location optimization model with the smallest operation cost based on the composition of the cost of China Railway Express operation, and designs a multi-population genetic algorithm to solve it. Secondly, a transportation network composed of 20 cargo source areas, 3 alternative assembly centers, 4 ports, and 3 destination cities was selected as an example to conduct analysis and verification, determine the optimal location strategy. Finally, this article draws conclusions and suggestions, which can provide reference for the construction of China Railway Express assembly center.