The invention relates to an SAP-based iron and steel industry internal transaction service order automatic creation method, which comprises the steps of establishing a data platform in an SAP system,and providing a data basis for processing inter-company service circulation; setting a timing task in the SAP system, and achieving timing updating of the data platform; setting an interface specification for the SAP system to receive inter-company transaction service messages; analyzing the message information, and automatically creating an inter-company business order; and automatic monitoring business order creation between companies. According to the invention, dynamic creation of orders in a business exchange process between companies in an iron and steel enterprise group is realized; product information and company information in cross-company businesses are obtained by means of building a data platform, designing external interfaces and the like, accuracy and uniqueness of data in the logistics allocation process are guaranteed, meanwhile, wrong order data are automatically checked and processed through programs, business requirements are met, meanwhile, business operation is simplified, and working efficiency is improved.