In order to adapt to the characteristics of cruise-type stamping extended-range guided artillery shells that the center of mass is constantly moving forward during cruise flight and the range of aerodynamic parameters is large,and in order to realize adaptive control during cruise flight,a three-loop autopilot based on fuzzy adaptive PID algorithm is designed.Firstly,the small perturbation method is used to linearize the system of shell motion equations in the longitudinal plane and deduce the transfer function of each attitude angle of the shell,and the feature points at the beginning and end of the cruise are selected for dynamic characteristic analysis.Based on this,a three-loop autopilot is designed to increase the phase angle margin of the system and improve its damping characteristics.The inner-loop control parameters at the feature points at the beginning and end of the cruise are designed by using the frequency domain analysis method and the root trajectory method,and the inner-loop control parameters of other non-feature points are calculated by interpolation.The outer loop is designed by using fuzzy adaptive PID.The simulation results show that the autopilot designed by the fuzzy adaptive algorithm has good control quality during cruise flight.