This paper presents design of wireless sensor network node based on CyFi and ARM7 system. The system is based on ARM7 system with high performance and low power LPC2214 as hardware platform, and the system is designed based on the principle of modular. This paper designs the nodes in wireless sensor network and gets the infrared sensor circuit, RF communication circuit, and peripheral interface circuit design and data transmission process together. In this paper, using the CyFi wireless sensor network, and through the implementation of binding and data nodes collection of USB interface in the PC machine. The experimental results show that the mobile node is suitable for dynamic information in wireless sensor networks, complex tasks. The sensor node has the characteristics of simple configuration, easy expansion, and high reliability