Abstract: To widen adapted antenna pattern troughs on Gram-Schmidt(GS) algorithm in adaptive digital beamforming(ADBF), a mathematical model of adding more discrete interferring sources was constructed to change the interferring signal subspace, and then modified the covariance matrix of array snapshot data, while furthermore GS orthogonalized the covariance matrix.In the condition of high interference noses, adjusting the position and number of discrete interferring sources can obtain the expected trough width.The method is simple, easy to use and adds few load based on conventional GS algorithm.Computer simulation results showed validity of the proposed method.