The invention provides a high voltage transmission corridor forest fire positioning method based on a holder attitude angle. The method comprises the steps that (1) a digital elevation DEM base map within +/-3km in the vicinity of a field monitoring device is acquired; (2) according to the holder attitude angle acquired by an angle sensor, whether the DEM digital elevation is greater than the height of the optical axis direction of an infrared lens is judged to determine the interval of a fire point; (3) a binary search algorithm is used for converging to accurately determine the location of the fire point; (4) according to the coordinate of installation point of an infrared thermal imaging forest fire monitoring device, the fire point coordinate is acquired to complete the calculation of fire point location; and (5) according to the coordinate information of the existing tower line and the information of the fire point coordinate acquired in the step (4), the shortest distance between the fire point and a nearby high-voltage transmission line is calculated. A reliable basis is provided for determining the risk level of line tripping caused by the forest fire. The safety of power grid devices is protected.