Abstract: During the construction process of TBM assemble hole ledge beam, because of the geological conditions and arti-ficial influence factors, the ledge beam could not be formed or there would be some defects in rock bench of ledge beam, which were serious security risks to the next installation of crane track in upper part of ledge beam.With the research back-ground of TBM assemble hole ledge beam of the 3rd contract section in main channel of transferring water from Songhuajiang River, the detailed analysis and study were carried out to put forward processing technology of ledge beam defects.The ver-ified research results have some reference values to the similar project.