The invention relates to a calculation method of power transmission line flashover caused by fire point data based on satellite remote sensing. According to the method, the fire point data of mountain fire are acquired through analysis of a satellite remote sensing image; the power transmission line space data are overlapped with the fire point data so as to obtain the possibly affected power transmission equipment information in a power grid system; the spread direction and the spread rate of the mountain fire are calculated by using a Rothermel model; the power transmission line covered by spreading of the mountain fire is obtained according to the spread direction and the spread rate of the mountain fire; the threshold height of flashover of the power transmission line is calculated through temperature field approximate simulation corresponding to spreading of the mountain fire; and when the height of the power transmission line covered by spreading of the mountain fire is less than the threshold height, the flashover power transmission line in the power grid system and the equipment information can be calculated. With application of the method, the burning rate, range and the covered power transmission equipment information of the mountain fire can be timely and accurately known, and the line and pole information having the possibility of line flashover can also be judged so that the power transmission safety can be guaranteed in a targeted way.