Modulation transfer function resulting from random vibration was analyzed. To conclude that the effect of angular displacement was the major factor. Allowable MTF degradation was represented, and convert allowable MTF degradation into stable system design parameters, which can guide perfect design for stabilization system. Based on the spatial mechanism and translational principle of parallelogram, an irrotational displacement isolator was developed. It can meet the requirements of irrotational displacement and damp. An instance was given; and 34dB reduction was achieved at frequency of 100HZ. With the help of MSC.ADAMS simulation software, simulated curve proves correct for isolator, and the irrotational displacement mechanism was tested by optical method, coupled angle is less than 8″, it can satisfy the demand of aerial imaging.