High-resolution imaging avian is quite significant for aviation security. Aimed at improving the lower resolution of the existed radar, an idea about avian detected and imaged by using inverse synthetic aperture imaging lidar (ISAIL) was proposed. The principle sketch of the avian ISAIL system was given, and a new sparse synthesizing method based on compressed sensing (CS) was proposed. By using the proposed method, the exact high-resolution cross-range profile can be achieved with the incomplete effect data. This method is robust. The effectiveness of the proposed method can be validated by simulation results.