Abstract: In view of the higher sidelobes and unsteady interference suppression of the traditional minimum variance distortionless response (MVDR) beamformer, an adaptive beamforming algorithm with controllable sidelobe is proposed. The algorithm firstly performs adaptive beamforming on the basis of MVDR, and then it performs peak search on the obtained beam pattern and sorts the obtained peak points from maximum to minimum. After that, the secondary maximum is taken as the value of the highest sidelobe to compare with the expected sidelobe value, and then it is suppressed by adding a virtual interference in its direction. Therefore a new beamforming pattern is obtained. Next, the peak search and other operations are once again carried out on the new beamforming pattern, and all the above iteration processes are continually repeated until reaching the expected sidelobe value. Computer simulation results show that the algorithm can rather robustly control the sidelobe below the expected level.