Random phasing is an effective measure for restricting the parasite lobes produced by phased array antenna. On statistically average optimal results, the antenna pattern of random phasing varies with the scanning angle and scanning period, it is difficult to produce the codes required for the control of antenna scan. Swarm Optimization Algorithm is used to restrict the parasite lobes and generate the required beam scanning codes, so as to achieve the precise point. The result showed that Swarm Optimization Algorithm is used to keep steady and optimal phase distribution for the phased array antenna.