The invention discloses a three-dimensional forest fire spreading simulation method and system. The method comprises steps of S1, three-dimensional landform factor generation; S2, three-dimensional wind field stimulation, on the basis of the data of a digital elevation model, wind speed and wind direction simulation is carried out, and the wind field data of a three-dimensional landform is acquired; S3, temperature field and humidity field stimulation, on the basis of the discrete temperature, humidity and digital elevation model data, interpolation processing is carried out; S4, combustible coefficient division, three-dimensional combustible coefficient data distribution is generated on the basis of the forest type distribution data; S5, three-dimensional fire field spreading simulation, a three-dimensional fire field spreading model is generated on the basis of a three-dimensional gradient, a slope direction, a wind speed, a wind direction, temperature, humidity and a combustible coefficient factor; and S6, three-dimensional fire field spreading information acquisition. The method is advantaged in that the method is applicable to forest fire spreading simulation, and a more precise simulation result can be acquired.