Abstract: The on-line monitor system for the implementation of technical specification for 10WM High Temperature Reactor （HTR-10） is based on data supplied by HTR-10 instruments and control system, which intelligently simulate the behavior of operators, analyze and judge in real time whether the state of reactor system and instruments is accordant with the technical specification standard, and at the same time auto-matically conduct some periodical tests and checks in specified frequencies and reminds the operators of the checks that can not be conducted in time. It can avoid the negligence by manual check of the implimentation of the technical specification. This paper introduces system model, composition modules, technical devel-opment characteristics and method in the practical application.