The invention relates to a method for quickly computing elasticity deformation of a deep groove ball bearing and an angular contact ball bearing based on FFT (fast fourier transform), and belongs to the technical field of optimizing design of rolling bearings. The method is based on a point contact stress distribution and influence coefficient matrix of the deep groove ball bearing and the angular contact ball bearing, a discrete cyclic convolution theorem and an FFT technique are applied into the elasticity deformation computing of the bearings, and the elasticity deformation amount between a rolling body and an inner ring or an outer ring, and the total elasticity deformation amount of each rolling body, each inner ring and each outer ring are computed. The method has the advantages that the problem of low computing efficiency of the traditional method is effectively solved, since the complicated quadruple cyclic computing is required when the elasticity deformation of the deep groove ball bearing and the angular contact ball bearing is computed by the traditional method, the memory of a computer is seriously consumed, and the computing amount is large; by correctly applying the discrete cyclic convolution theorem and the FFT technique, the elasticity deformation of the bearings in the computing area can be accurately and quickly obtained.