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It is significant to efficiently and accurately determine the flutter boundary of various aircraft configura-tions in the aircraft design. In this paper, the linear unsteady aerodynamic method and nonlinear unsteady aerody-namic method are adopted for the subsonic and transonic areas, respectively. In the nonlinear method, the transonic small disturbance equation based on the accuracy steady CFD results is used as inputs. The <i>g</i> method is used in all flutter solutions for different Mach areas. The flutter analysis is used for an beam and reduced stiffness FEM model of the whole aircraft including empty aircraft and three special fuel cases for choosing the typical altitudes and Mach number covering the flight envelope and determine the flutter envelopes for the four aircraft configuration. Results show that the flutter boundary of the aircraft is consistent with flight flutter test. Compared with other analysis meth-ods, the efficiency is obviously improved, especially for a variety of aircraft configurations. Therefore, the method adopted in this paper is an efficient and accurate method for predicting flutter boundary of large aircraft, which is suitable for engineering at present.