In order to solve the problem of maintaining the pitch angle and ground horizontal angle in real time during the 360° panoramic scanning of search and track system on the moving base, an automatic leveling control technology was designed. On the basis of rate closed-loop stabilization, the tilt sensor was adopted to constitute the spatial position loop, which formed the double closed loop of position and rate, and the automatic leveling of the system line of sight was realized. Aiming at the automatic leveling technology, the key of platform control, the spatial position loop constituted by the tilt sensor and platform gimbal angle was emphatically analyzed. The relation between line of sight and horizontal plane angle of search and track system was theoretically deduced, and the system control was analyzed and simulated. The final simulation analysis results are basically consistent with the actual test results and meet the index requirements of the system.