In order to improve the efficiency and quality of the teaching service of the national musical instruments, a design method of product service system (PSS) for national musical instruments is proposed to build a tool for integrating teaching resources, autonomous practice feedback, and social interaction. The basic characteristics of the national musical instruments of the balance between the improvement and the inheritance of traditional music is summarized, the shortcomings of digital transformation of national musical instruments under the condition of smart technology are compared and pointed out, there is still room for development in precision teaching services. Based on the design method of PSS, the musical instrument products and teaching services are integrated into an overall solution, a model of teaching service and value co-creation is constructed. A service process is formed with the song as the basic teaching unit and gesture skill training as the key. The human-smart system collaboration mode is analyzed. The smart product subsystem and teaching service subsystem are established. The relationship among the stakeholders is discussed. The prototype scheme of the smart assistant teaching system of Pipa based on this method is built up to verify.