RangeDoppler algorithm (RDA) is a basic method in synthetic aperture imaging. In RDA, the Doppler frequency is considered as constant, but this hypothesis is not existed in synthetic aperture ladar(SAL). Based on the echo signal model of SAL, the influence of vibration error on the phase is computed and analyzed. On the reference of the national military standard for environment, in the condition of the frequency below 500 MHz and the amplitude below 0.2 mm, the simulation results show that the influence of vibration on the azimuth resolution is severity, but which on the range resolution is trivial. The imaging algorithm based on timefrequency analysis can overcome the limit of traditional RD algorithm effectively. Compared the imaging results used WVD, PWVD and SPWVD as kernel, they cannot suffice both the imaging resolution and imaging efficiency. A combined timefrequency imaging method based on adaptive windowing is presented to modulate the window size adaptively according to the comparison of variance coefficient and variance threshold, then the counterpoise optimize of imaging resolution and imaging efficiency is achieved. The simulation results show that the imaging resolution of this algorithm is constant, but the imaging time decreases 69.87%, and it can used in SAL for its high imaging resolution and imaging efficiency.