Synthetic Aperture Ladar(SAL) is the focus of remote sensing research in recent years with vibration as an important issue in this system. According to the research before, SAL is sensitive to the cross-trace line vibration. In order to eliminate the phase error brought by vibration, the staggered structure of two sub-apertures along range direction was proposed according to the principle of differential synthetic aperture ladar (DSAL). Using the measured POS data, the ability of eliminating the effect of line vibration of this staggered structure was analyzed in principle. Analysis was also made about the effect of angle vibration on this structure. The results show that the structure can eliminate the effect of line vibration as well as angle vibration. The results provide theoretical foundation and system choice for vibration elimination in SAL imaging in practice.