The present invention provides an insulator pollution dynamic prediction method in a natural environment. The method comprises the following steps of: S1: collecting weather parameters and insulator parameters of an environment where an insulator is located, and determining that the insulator is in a rainfall erosion process or a pollution process according to the weather parameters; and S2, establishing an insulator rainfall erosion model and a pollution material quality concentration model at unit area of the insulator, and calculating pollution grade in the rainfall erosion process and pollution amount in the pollution process according to the rainfall erosion model and the pollution material quality concentration model. The insulator pollution dynamic prediction method in the natural environment comprehensively considers factors of the environment where the insulator is located, can accurately perform prediction of the pollution condition of the insulator so as to facilitate makingof accurate and timely response measure according to a prediction result and ensure safe and stable operation of a power grid.