In this paper, we propose an iterative algorithm, which can achieve beampattern control and adaptive beamforming at the same time. Our proposed algorithm is computationally efficient because it avoids the calculation of matrix inverse which is often required by conventional beampattern synthesis algorithms. Besides this advantage, the new algorithm is superior in being able to shape the sidelobe region which is left uncontrolled by other adaptive beamforming algorithms. Numerical results show that our proposed algorithm has the ability of nulling out interferences and maintaining a well-shaped beampattern simultaneously.