The present invention relates to a modal frequency of wind turbine blades and a bimodal Gaussian distribution fitting method for the same. The method comprises the following steps: 1) using an entity model of wind turbine blades as a research object, establishing a structure motion differential equation according to the principle of instantaneous minimum potential energy and solving the characteristic equation by using a Block Lanczos method; 2) calculating top ten modal frequencies of wind turbine blades under different rotating speeds by using finite element analysis software ANSYS to obtain two different variation patterns of the modal frequencies changing with rotating speeds and providing corresponding variation mechanism analysis; and 3) performing bimodal Gaussian fitting on changing curves of first and tenth modal frequencies of wind turbine blades under different rotating speeds and implementing comparative verification. Compared with the prior art, the method has the advantages of high accuracy, etc.