This paper designs a way to introduce Zig Bee technology into the ranch fire monitoring system,and builds a real-time ranch fire monitoring system based on Zig Bee wireless sensor network.The system can monitor the parameters related to ranch in real time,such as air moisture,temperature and smoke density,so as to provide information support for ranch fire prevention and extinguishment.This paper researches the circuit design of Zig Bee wireless sensor network node,node information collection,data fusion,transmission and effective topological structure of sensor network.