In order to ensure the quality of spacecraft control software products, a method for analyzing the interface data requirements of spacecraft control software application layer is proposed. According to the specific model, the application layer interface data (application layer API) is obtained by analyzing the external single machine with the object-oriented method; the core business of attitude and orbit control is separated from the support business such as communication, protocol, data processing and component management, and the communication interface between the core business and the support business is determined. The results show that the method can improve the independence of software function and the flexibility of software architecture, reduce the complexity of software development, organize all external stand-alone and control computers of attitude and orbit control subsystem into an organic-whole, and ensure the high cohesion and low coupling of software products in 2 dimensions of function and design.