In optical wavelength scale, any targets can be hardly regarded as stationary. Therefore, target vibration may affect synthetic aperture ladar (SAL) imaging severely. To address this problem, the imaging mathematical equation of strip-map mode SAL, in which quasi-monochromatic chirp laser is used as the illumination source in the situation of target vibrating, is set up. Using this equation, the effection of the vibration parameters is analyzed and discussed, and some simulations for this are performed. The result shows that SAL imaging is extremely sensitive to the target vibration. Tiny target vibration in range may bring a series of false images in azimuth to the final SAL image and seriously affect the realization of a high resolution SAL imaging.