A characterization method for optical free-form surfaces based on Gaussian radial basis functions is disclosed, by clarifying the expression of Gaussian radial basis functions, obtaining the data point set to be fitted to the optical free-form surface to be fitted, and normalizing the data to be fitted , Calculate the gradient vector according to the normalized data to be fitted, analyze and process the gradient vector, divide the sub-aperture, set the number of Gaussian radial basis function bases, obtain the number of Gaussian radial basis functions in each sub-aperture, and obtain the Gaussian radial basis function The total number of basis functions, the center point of the Gaussian radial basis function uniformly distributed in the sub-aperture, the optimal value range of the coefficient A, the final fitting effect, and the final total number of basis functions are specified, so that complex optical free-form surfaces can be processed High-precision characterization can meet the needs of modern optical system design, processing and testing. This method is simple to calculate, easy to implement, and has strong surface shape adaptability. It is suitable for any caliber and can realize high-precision characterization of optical free-form surfaces.