The airborne synthetic aperture radar（SAR） system realizes the large azimuth width by scanning. The scanning angular velocity is restricted by azimuth resolution， squint angle and other parameters. It is a difficult problem to design and implement airborne wide-width azimuth scanning SAR with both scanning efficiency and azimuth resolution. In order to realize azimuth wide-swath scanning in the air route， a beam control method is proposed. By deriving the scanning angle change rule between different scene images， and designing the start scanning angle and end scanning angle of each scene image according to the angle change rule， the designed beam control method can meet the resolution requirements of the scanning angle velocity of each scene image and has a time-varying angular velocity with a high scanning efficiency. Overlapping between scenes to ensure coverage and the target scene is located in the middle of the scanning width in the course.