In order to realize defect inspection for train wheel treads,a defect inspecting system of the train wheel treads based on computer vision is established and defect region extraction techniques for the images of the train wheel treads are investigated.The tread region is extracted by an adaptive thresholds algorithm,then,a method combining the approximate location based on the block segmentation with the accurate location is adopted to extract the burning defect regions,and the peeling defect extraction method based on searching tread edge lines is used to extract the peeling defect regions.Two experimental examples are carried out to verify the effectiveness of the proposed method.The experimental results indicate that the missing recognition rates of the burnings and peelings are 8.3% and 5.3%,respectively,and false acceptance rate is 5.1%,which shows that proposed method can lay the basis for the feature extraction and defect recognition further.