In synthetic aperture radar (SAR) imaging system, vibrating target imaging possesses the Doppler characteristics of paired echoes, which is not conducive to the detection and identification of vibrating targets. A vibrating target imaging method based on phase retrieval principle is proposed in this paper. Firstly, according to the stripmap SAR imaging mode, the geometric model of vibrating target is established, and the possibility of applying the phase retrieval principle to the SAR vibrating target imaging is deduced theoretically. Then, taking the echo data of SAR vibrating target and support domain information as the prior information of the oversampling smoothing (OSS) iterative algorithm. through changing the parameters of the smoothing filter to adjust the filter bandwidth, the interference of the external support domain information to the vibrating target is reduced, At the same time, through reducing the size of the support domain, improve the convergence of the iterative algorithm and eliminate paired echoes of vibrating target, finally the focused high resolution image of the vibrating target is obtained. The simulation experiment results prove the effectiveness of the proposed method.