A numerical simulation method for characterizing fluid channeling along large-aperture fractures of reservoirs relates to the field of petroleum reservoir development research and computational fluid dynamics. The conventional method can not effectively represent the rapid fluid channeling along large-aperture fractures. Aiming at solving the above technical problem, an advanced method is provided in the present invention. In the invented method, the geometric similarity and hydraulic similarity treatments of large-aperture fractures can be made simultaneously, moreover, the traditional numerical simulation software was improved to be an unstructured grid simulator. Therefore, the method of the present invention can effectively simulate the rapid fluid channeling along large-aperture fractures, consequently it can ensure the reliability of the simulation results and provide reasonable reference for the adjustment and optimization of oil field development plans. The present invention is simple in principle and easy to use, thus it has a great value of application and popularization.