Abstract:Implementation methods of component-based software are put forward in the open Networked Automatic Test System (ATS), which lays the foundation for the system software reuse. The thought of Domain Engineering is introduced into the development process and divides the whole process into three phases. In the domain analysis phase, the Unified Modeling Language (UML) is used to perform requirement analysis, static analysis and dynamic analysis of the test system. In the domain design phase, identification and extraction of reusable components are accomplished on the basis of the achievements in domain analysis. In the domain realization phase key, reusable components in the test system have been realized.