In the light of the problem of monitoring forest fire, the design strategy and practical implementation of establishing the fire monitoring system based on digital image information are proposed. The system is based on the continuous image sampling provided by CCD camera. We can obtain the configuration characteristics, dynamic characteristics and color information of interesting region with an application of the digital image processing algorithm, and then to identify the fire source according to the acquired characteristics. The experimental results show that the system can accurately identify and confirm the fire. Besides, the amount of data processed can be reduced because of the use of sampling algorithm thus shortening the execution time.