Due to the short laser wavelength, almost all practical targets are rough. Surface elevations in rough targets will result in layovers in synthetic aperture ladar (SAL). High resolution SAL image with layovers will be different fi'om the target picture taken by incoherent tools as digital camera. To investigate the layovers in SAL image, a simplified mathematical model is built by optics diffraction theory and a laboratory SAL is setup using 1550 mn tunable laser source. Layovers in SAL images, in both theoretical simulation and experimental demonstra- tion, are carefully observed. Detailed results on various targets are illustrated.