To solve the problems of production capacity information acquisition and modeling in the business-control integrated manufacturing system, oriented to complex discrete manufacturing process, a production capacity model based on ISA-95standard was proposed which was extended from the dimensions of organization, calendar and resources. The model architecture was defined by B2MML language which was used for information exchange in system integration. Due to the fact that ISA-95standard production capacity model only defined the competencies property of resources, the bottom-up calculation method of production capacity based on extended model dimension was proposed, and calculation formula for each layer was also defined. Under the make-to-order environment, production capacity was the important information of CTP calculations which was feed back to the business system from the manufacturing system timely and accurately. The reliability of the commitment order was improved, and the validity of the model was proved.