in recent years, wireless technologies have been employed by Perimeter Intrusion Detection Systems (PIDS) to reduce the cost of wiring, especially for some secure sites which are not wiring-friendly. However, the PIDS based on state-of-art wireless media such as WLAN, ZigBee, or UWB, suffers from remote distance and noisy wireless links which are easy to fail due to obstacles, signal shadowing and fading. In this paper we propose a PIDS using GPRS and CDMA dual-mode wireless sensor networks (DM-WSNs) to deliver an optimal data transmission service. Moreover, Auto Shutdown mechanism is proposed to address the energy conservation for battery powered sensor devices. We deploy the DW-WSNs in the PIDS of an airport in China, to safeguard the parking apron against illegal intrusion. Practice experience indicates that the DM-WSNs can achieve a better network quality and fully satisfy the first-response requirement of airport security.