The invention relates to a method for detecting an irregular circle based on Gauss pyramid decomposition. The existing circle detecting algorithm has the defects of error detection and omission detection in a high resolution ratio and multi-circle detection environment. The method comprises the following steps: aiming at a circle target in a digital image, decomposing an image into images with different resolution factors through a Gauss pyramid decomposition method; aiming at different levels of resolution factors, carrying out rough detection on an image with a lower resolution factor by using a detection method of different circles; and then carrying out precise circle detection on an image with a higher resolution factor, wherein in each detection step, a specific setting method is given for a corresponding threshold. By utilizing the method, the detection precision of irregular circle is improved and high-noise and multi-circle complicated images can be analyzed.