Abstract: Abstract: The reactor core model for a single power level can not accurately represent the dynamic characteristics of the core under different power conditions. In order to solve the problem, the triangle membership function is used to weigh five local models at different power levels, and the fuzzy multi-model simulation system is developed. Taking the PWR core as an example, the disturbance simulation of the reactivity and the coolant inlet temperature are carried out. The results show that the fuzzy multi-model simulation system can be applied to the simulation of different core power levels.