The cross-track baseline component of the along-track interferometry processing baseline is introduced by the angle of pitch and yaw in the actual flight, and the accurate imaging of elevation fluctuation terrain is difficult to obtain under the condition of vibration. In order to realize vibration estimation in airborne synthetic aperture ladar (SAL) effectively, a kind of vibration estimation and imaging method is proposed based on interferometry processing of three detectors with orthogonal baselines, and the signal model is established and its accuracy is analyzed. This method need to make the field of view overlap, and it is realized by the characteristic of SAL non-imaging optical system. The optical system containing a wide swath ground imaging detector and three vibration estimating detectors is introduced. The impact of overlapped degree of field of view of detectors and signal-to-noise ratio on performance of vibration estimation are discussed respectively. The imaging simulation results of the elevation fluctuation terrain under platform vibration condition validate the effectiveness of the proposed method.