This paper discusses in detail the four methods of determining the length of anchorage section of prestressing anchor cable, and points out the advantages and disadvantages of various methods and the application of the precautions, focusing on the field test method of site selection, construction points, the collection and processing of test data, etc., compared with the other methods, the anchorage length determined by the field test method is more in line with the actual engineering, and therefore more reliable, is the anchor cable project, especially the large-scale anchor cable project, the preferred method of determining the anchorage section length.