A layered parallel iterative chaincode tracing line extraction method is proposed. Firstly, based on the hierarchical parallel structure, the image is divided into several independent subregions with increasing radii according to the hierarchy. In the processing of the first layer, based on the existing chaincode tracking method, corresponding improvements are made in the selection of tracking starting point, chaincode tracking processing, and straight-line segment extraction, and the extraction of line segments in each sub-region is realized in parallel. In the upper sub-region, according to the linear segment information of the secondary sub-region, four types of non-overlapping window marker processing are introduced to carry out efficient iterative processing of connection and merging, and realize the acquisition of image straight segments. This method has good real-time and detection accuracy, and maintains the information such as the end point and length of the straight line. Experimental results prove the effectiveness of this method.