Abstract: In order to improve the stability of anti-interference performance of array antenna, a zero-notch broadening method based on side-lobe cancellation algorithm is proposed in this paper. Two side-lobe cancellers are used to realize the communication function of dual function radar antenna in both active mode and static mode, and the interference can be effectively suppressed in both modes. Then, the method of null broadening is introduced to make the interference point null spread in both modes. In this way, the interference can also be well suppressed when it fluctuates in a certain range, thereby the stability of the anti-interference performance of the array antenna can be improved. In this paper, 11 array antennas are simulated. By comparing the array beam-forming with side-lobe cancellation algorithm and several zero-notch broadening techniques, the effectiveness of the proposed method is verified.