Array-InSAR tomography has become a field of intensive research to reconstruct urban 3D point clouds. However, multipath interference is very obvious in the reconstructed 3D point clouds, seriously affecting the recognition, extraction, and modeling of the building. In this letter, the authors proposed a novel multipath suppression method to improve the quality of point clouds, which mainly utilizes the characteristics of secondary and tertiary scattering. The performance of the method is verified through airborne array-InSAR data. Experimental results show that the proposed method can automatically obtain large scene urban 3D point clouds without multipath interference.