To detect the center and radius parameters of defect circle, the paper proposes a detection method based on random sampling and voting strategy. Through randomly selecting three points from the target edge, two arbitrary chords are obtained, and the intersection points of two vertical bisectors are calculated. Several candidate center coordinates are obtained by repeating the above process. By using voting strategy, one can extract the coordinate value holding the highest frequency and so the ideal circle’s center is detected. Then the radius parameter is obtained by using the voting strategy again. The results of simulation and experiment show that the proposed method has strong adaptability and robustness and may be applied to different types of defect circle. In addition, it is accurate and reliable, easy to realize, and can meet the requirement of engineering application.