In this paper, LMI (Linear Matrix Inequality) based on H$\_$$infty$/ controller for a lire of sight (LOS) stabilization system. It shows that the proposed controller has more excellent stabilization performance than that of the conventional PI-Lead controller. An H$\_$$infty$/ control has been also applied to the system for reducing modeling errors and the settling time of the system. The LMI-based H$\_$$infty$/ controller design is more practical in view of reducing a run-time than Riccati-based H$\_$$infty$/ controller. This H$\_$$infty$/ controller is available not only to decrease the gain in PI-Lead control, but also to compensate the identifications for the various uncertain parameters. Therefore, this paper, shows that the proposed LMI-based H$\_$$infty$/ controller had good disturbance attenuation and reference input tracking performance compared with the control performance of the conventional controller under any real disturbances.