Abstract: The fatigue monitoring system collects the operation parameters of the primary loop and equipment prone to heat fatigue, and fast fatigue analysis method was used to conduct the real-time fatigue calculation of the pipe and equipment which were monitored, to obtain the real fatigue damage. The fast fatigue analysis method was based on the Green function method, and the fast calculation of thermal stress and fatigue coefficient is conducted by compiling the calculation program. By comparison with the result of finite element analysis, the fast fatigue analysis method is proved to be efficient, fast and accurate.