To overcome the technology barriers of the traditional test method in testing digital circuit board, put forwards a new design scheme of missile equipment built-in self-testing based on missile data bus and boundary scan. Discuss the basic concept of system testing by introduce of the module test and maintenance bus (TM Bus) and boundary scan. A test system is designed to illustrate the concept and test the main indicators of design for testability (DFT). Performance testing indicates that the design can simplify testing process and improve the reliability, maintainability and testability of missile weapon system.