The invention provides an image processing method for detecting a similar round by using improved hough transformation. The method comprises the following seven steps of: preprocessing an image, extracting an edge and filtering out noises, weighing along a gradient direction and projecting the hough transformation, performing low-pass smooth filtering on a projection space, contracting and binaryzing, positioning a circle center and estimating a radius. Compared with the conventional method for detecting the round by using the hough transformation, the method has the advantages that: on the one hand, the requirement of an algorithm on a memory is reduced and the algorithm efficiency is improved; on the other hand, the performance of the algorithm for detecting irregular similar round objects is improved; meanwhile, the detection precision of the algorithm under the condition of a larger variation region of the round radius is enhanced.