With the rapid growth of natural gas demand, there is an urgent need to consider the production, supply, storage and marketing structure of natural gas pipeline network, optimize the natural gas sub-customer sales scheme based on system analysis and decision-making theory, and maximize the profitability and economic benefits. With the objective of maximizing the annual total benefit of the natural gas sales pipeline network of the provincial company, taking the gas supply volume from the gas source, the pipeline transmission volume, and the sales volume of the customers as the decision-making variables, and taking into account the node flow balance constraints, the upper and lower limits of the gas volume of the production, supply, storage, and marketing links, the total sales volume of the sub-province constraints, etc., we optimize the gas procurement costs, pipeline costs, storage and transfer costs of storage reservoirs and LNG receiving stations and the customer sales revenues of the gas supply network of the industry chain in the upstream, midstream, and downstream segments. The customer sales revenue adopts the step pricing method, establishes the mathematical model of natural gas customer sales volume optimization, and selects GUROBI solver as the optimization calculation tool to solve the model. The model is tested on the basis of basic data of natural gas pipeline network of a province in the next 10 years to maximize the benefits while meeting the customers' natural gas demand, which verifies the reasonableness and accuracy of the model, and provides advanced analytical tools and technical methods for improving the quality and increasing the efficiency of the natural gas sales business.