The active laser detection technique has a broad application prospect in the antimissile and air defense. However, the aerodynamic flow field around the planes and missiles causes serious distortion effect on the detection laser beams, according to the complicate physical process of the laser propagation in the“cat-eye”lenses and aerodynamic flow field, distortion propagation calculation method is performed. The physical optics propagation equations for the incidence and reflection process are calculated using Collins formula and angular spectrum diffraction theory respectively. In addition, turbulent performance of the aerodynamic flow field is estimated according to the propagation theory through a random medium, the root mean square (RMS) optical path difference (OPD) and Strehl ratio of the turbulent optical distortion are obtained. Computational fluid mechanics and propagation distortion calculation of the detection laser beam are performed with the hemisphere-on-cylinder turret as an example.