Theoretical analysis and simulation were made for near-field small system imaging of reflective tomography laser radar. In the Rayleigh-Sommerfeld diffraction domain,wavefront of the target belongs to spherical wave diffraction. According to Nyquist criterion,the constraints including the number of sampling angles and the number of sampling points in each projection for spherical wave reflective tomography were obtained. Broken lines method was introduced to avoid square and extraction operation and shorten imaging time. The simulation results show that double broken lines method was effective in solving the computational complexity problem in image reconstructed. Also with the increasing distance between the detector and the target,images reconstructed by the double broken lines method are close to the reference image.