To address the difficulty in quantitatively calculating the distribution of navigation errors in aircraft using the SINS/satellite combined navigation system, a linear model for integrated navigation was established based on the assumption that the initial alignment misalignment angle on a mathematical platform is a small quantity; Then, based on the analysis of the distribution characteristics of gyroscope, acceleration error, and system error, a calculation method for the error distribution of the integrated navigation system was proposed; Finally, the SINS/ satellite navigation error distribution calculation system was designed. By applying this calculation system, the distribution characteristics of terminal navigation errors of the aircraft in both pure inertial navigation and integrated navigation states were analyzed in detail. The impact of the SINS/satellite combined navigation method method on the terminal navigation error of the aircraft was evaluated, and the simulation results verified the correctness of the proposed method and system design in this paper.