Backscattering lidar is a powerful tool for atmospheric aerosol detection, but the blind and transition regions restrict its detecting range and precision in near distance. Side-scatter lidar based on charge coupled device (CCD) can detect aerosol continuously in near distance with great precision. The characteristics of interference light and background light in side-scatter lidar are analyzed, and the way to decrease them is found. The characteristics of atmospheric scattering light generated by laser are analyzed, and the scattering light superposition from the same distance is computed. Matlab software is applied to retrieve signals, and the comparison between the proposed method and the backscattering lidar signals is made. The result indicates that this retrival method is reliable and feasible.