Abstract: The production plan, as the start and the proof of production management, aims to avoid manual production planning causing the waste of resources and to achieve the optimal production planning strategy. Based on Electric Resistance Welding (ERW) steel pipe enterprises′ production characteristics, the production plan is optimized. In mathematical modeling, a mathematical model of earliness/tardiness punishment for multistage production plan was established with the limitation of the due window, inventory, production capacity, maintenance shutdown date etc., aiming to optimize the production plan and to minimize the tardiness punishment. The mathematical model was solved and optimized through genetic algorithm. In developing the management information system, the B/S model information system with Visual Studio 2010 on the basis of the database was created. With the linkage of MATLAB and B/S system through the COM port of MATLAB, the algorithm was perfectly embedded with a user friendly interface and in turn realized the calculation and expression of the production plan. The results show that applied in a specific enterprise, the model and management information system realized the management of the ERW steel pipes enterprises′ orders, inventory and production plan data management, achieving the expected goal, with a good academic value and practical significance.