Cotton is a strategic material for people’s livelihood, however, its fiber is most combustible in all kinds of natural fiber. To warn this risk, the mechanism of cotton pile smoke and fire was studied in this paper, and the monitoring and early warning indicators of the cotton pile fire were selected. The multi-sensor array was designed and to developed sense temperature, humidity and CO concentration. The fire monitoring device has the key modules of temperature sensor, humidity sensor, CO gas sensor, and PC center. A user interface was developed on LabVIEW to display and control data. Multi-sensor array based fire monitor can provide the data of temperature, humidity and CO concentration. It is essential to effectively measure abnormal or normal situation of the cotton pile, and can make early warning for the cotton fire and reduce the loss of cotton fire disaster.