The invention provides a mountain fire monitoring system and method based on infrared guidance and radar detection. In the mountain fire monitoring system and method, an infrared sensor and a radar detection device are fixed and integrated on the same rotating platform driven by a servo motor, the infrared sensor is used for finding an ignition point, the distance of the ignition point is measuredby the radar detection device, the ignition point is positioned, the radar detection device is used for monitoring the topography and vegetation coverage condition in the area near the ignition point, and combined with the wind speed and direction at the time, the fire risk classification and warning of transmission lines are realized. The functions of automatic finding, automatic positioning andautomatic alarm are realized, the line tripping accident rate caused by a mountain fire is reduced, and the capability of electric transmission lines to resist mountain fires disasters is improved.