In order to improve the effectiveness and pertinence of TACAN jamming, and solve the problem that the jamming signals may disturb the civil signals and the own electronic systems, it is proposed to transmitte the jamming signals by array antenna. Based on the LCMV rule, the signals inputed to arrays are multiplied by multiple weight vectors and single weight vector respectively, and the two beam'forming methods are analyzed by simulation. The simulation results show that, when using array antenna for beam forming, the single weight vector has 2 degrees, 4 degrees and 4 dB advantages respectively in such aspects of half'power beam width, minimum spacing of the beam and power difference between the main lobe and the sidelobe.