The ldquominus beamrdquo steering of the phased arrays deviates from the given direction because of the quantization phase in the digital phased shifter. This paper studied the theory of wide-beam and ldquominus beamrdquo and investigated the model of the particle swarm optimization method on the arrayspsila beam steering, and modified the range of the position and speed factor by the principle of random phase quantization. The simulating results show the effectiveness and correctness of the method.