Abstract: The nuclear reactor is a complex nonlinear system with uncertain parameters and disturbances. Based on the self tuning model algorithmic control principle, a new thermal power tracking control method for the nuclear reactor is presented. The method can overcome the bad control quality of the normal multi step model algorthmic control method, while the big variation of the system parameters occurs or the estimated model is inaccurate. After comparing with the normal multi step model algorithmic control method, the simulation results show that the method presented in the paper makes the nuclear reactor system have stronger robustness and better performances.