A portable maintenance assistance (PMA) design scheme suitable to field level based on interactive electronic technical manual (IETM) platform is proposed. The main function and structure are described. The design schemes of hardware and software in PMA are introduced. The packaging and loading technology of TPS-COM is adopted to realize man-machine interactive operation to improve the compatibility and interoperability of multiple platforms, which further promote the development of informationization and digitization for equipment testing and maintenance.