The present application discloses a method for numerically simulating orthodontic effect of an orthodontic appliance. The method comprising: providing a numerical dental model representing a patient's dental tissues, wherein the numerical dental model comprises mechanical parameters and geometrical parameters of the patient's dental tissues; providing a numerical orthodontic appliance model representing an orthodontic appliance, the orthodontic appliance corresponding to an expected orthodontic state, and the numerical orthodontic appliance model comprising mechanical parameters and geometrical parameters of the orthodontic appliance; combining the numerical orthodontic appliance model with the numerical dental model to simulate wearing of the orthodontic appliance on the patient's dental tissues; calculating orthodontic change after the wearing of the orthodontic appliance on the patient's dental tissues, based on the mechanical parameters and geometrical parameters included in the numerical orthodontic appliance model and the numerical dental model respectively; and assessing the orthodontic effect of the numerical orthodontic appliance model based on the orthodontic change.