BiSAR has plenty of advantages, such as high imaging quality and easy concealing,but it seriously depends on frequency sources of the sender and receiver. As frequency source,crystal oscillator is widely used on composed aperture radar for its outstanding performance;but it is sensitive to vibration and impact and so on. This paper started with analyzing the noise characteristic of oscillator, and then the effect on SAR imaging of the stability of frequency sources was studied. An effective method for acceleration compensated was introduced, achieving improved compensation of 12 dB at 4 g@15 Hz phase noise.