At present, the diagnosis and treatment of early cancer in digestive tract is a hot topic, which is defined as cancer confined to the mucosa layer and submucosa, including early esophageal cancer, early gastric cancer and early colorectal cancer. For gastrointestinal cancer early diagnosis technology has been from a single common white light endoscopy, endoscopic gradually transition to the pigment dyeing narrow-band imaging technology, electronic (narrow band imaging, NBI), intelligent electronic spectroscopic techniques (flexible spectral imaging color enhancement, FICE), magnifying endoscopy, endoscopic confocal optical microscopy, confocal laser endomicroscopy, CLE), etc., so as to improve the early cancer detection rate, can even provide lesions in depth and scope, histopathology, and blue laser endoscope is introduced by the Fuji company blue laser endoscopic system (LASEREO), the more possibility for accurate diagnosis of early carcinoma of digestive tract. In this paper, the progress of blue laser imaging technology (blue laser imaging, BLI) in the accurate diagnosis of early carcinoma of digestive tract was overviewed.