Abstract: Objective:To investigate the pathological diagnostic value of gastrointestinal biopsy on high-grade intraepithelial neoplasia(HIN).Methods:A retrospective analysis of clinical and pathological information was done in 52 cases who were diagnosed as HIN by endoscopic biopsy,and the pathological diagnostic results were compared.Results:In total HIN patients,27 cases were diagnosed as the scope of endoscopic lesion was 3 cm,including 18 cases whose lesion was in upper digestive tract,and 13 cases were diagnosed as cancer with postoperative pathological analysis;9 cases whose lesion was in colon and rectum,1 case was diagnosed as cancer.There was statistical difference in the two groups(P=0.004).The ratio of cancer in upper gastrointestinal tract in these two groups whose lesion range was 3 cm or 3 cm were compared,there was no difference in two groups which diagnosed cancer in upper gastroinfestfinal tract regardless of lesion ragne(P=1.000);but there was statistical difference in colorectal patients whose lesion range was 3 cm or 3 cm(P=0.002).Conclusions:It needs to choose an active treatment when preoperative endoscopic biopsy is diagnosed as HIN in upper digestive tract.The surgical operation needs to be prudent when lesion range is 3 cm in colorectal lesion.