To deal with the problem of multipoint source interference including main lobe interference, the two methods of suppressing the mainlobe interference based on blocking matrix preprocessing and based on eigenprojection matrix preprocessing are quite good in antiinterference effect, and their main ideas are mainlobe interference eliminated by pretreatment of first, then the conventional adaptive beam formation, the implementation of the mainlobe interference suppression, but the two methods need to expect a prior information matrix to construct the pretreatment and interference .Aimed at the problem that the prior information fails to be obtained directly in the practical application, a new type of principal antimultipoint source interference algorithm without prior information is proposed in combination with the method of the preprocessing of the characteristic projection with the estimation of the arrival direction of the strong and weak signal. The simulation results show that the proposed method is fairly good in the effectiveness of antimultipoint source interference effect without knowing the prior information of angle.