Abstract: Considering the limitations of phase unwrapping and measurement mechanism in the pulsed radar phase ranging technology, a three-dimension (3D) ranging mechanism based on distributed radar is proposed, and the observation matrix model of distributed radar 3D ranging is established. By using the sequential phase difference caused by the distributed antenna layout instead of the phase difference caused by pulse incubation, a distributed wide-band radar (3D) measurement based on observation matrix is implemented, and in?combination?with the target sparse distribution characteristics in the observed area, a wide-band pulse radar carrier measurement by phase based on CLEAN method is suggested. As shown by the simulation and analysis results, the distributed radar phase ranging mechanism and method in this paper not only solve the phase unwrapping problem in high dynamic and long distance measurement environment, but also acquire the three-dimension sequential images and position information of the observed target quickly. This proposed method provides a new technical support for the application of the radar ranging technology.