Traditional fire monitoring systems usually adopt single sensor to detect fire by wire transmission systems, and they have inconvenient wiring, low environmental adaptability and poor anti interference ability. A fire detection system based on ZigBee wireless multi-sensor network is proposed with sensors including smoke, temperature and carbon monoxide gas sensor to detect combustion situation. The trust functions for smoke, temperature and carbon monoxide caused by fire are assigned according to fire situation, and the D-S evidence theory is utilized to integrate the three kinds of sensor information to determine whether fire happens or not. Multi-sensor combustion response experiments are conducted. Theoretical analysis and experimental results show that the fire detection system based on wireless multi sensor can detect fire more accurately, reduce the false alarm rate and improve the credibility of thesystem.