Abstract: Aiming at the problem of decreased positioning accuracy of traditional TDOA method in complex terrain environment, this paper proposes a TDOA positioning method improved by combining digital elevation model correction and particle swarm optimization algorithm. Firstly, the principle of traditional TDOA positioning method and its error characteristics affected by elevation changes are analyzed, and the positioning accuracy is improved by introducing DEM to correct the TDOA measurement error. In addition, dynamic inertia weights and improved velocity update strategy are introduced to optimize the traditional PSO grid search process, which effectively improves the global search capability and convergence performance of the algorithm. The experimental results show that the positioning error of the TDOA method with the introduction of DEM correction is significantly reduced compared with the traditional method in complex terrain, and the combination of PSO optimization significantly reduces the computation time while maintaining high accuracy, which improves the stability and applicability of the algorithm. The proposed method shows high accuracy and robustness in satellite TDOA passive localization.