Some tags in the radio frequency identification (RFID) application based on the surface acoustic wave (SAW) technique often locate in the field of a transceiver simultaneously, leading to difficult identification. In this paper, the digital beamforming technique is applied to identify multiple SAW ID-tags to address difficulties in identification. The direction of arrivals (DOAs) are used to denote the locations of the tags and the particle swarm optimization (PSO) algorithm is suggested to find the optimal estimates of the DOAs. Once the DOAs are obtained, the array weights are then formed and the signals of tags are recovered to implement decoding. The experiment results show that a good identification of multiple SAW ID-tags is achieved.