Objective:To explore the detection rate of non-caseating granuloma under endoscopy in patients with Crohn′s disease and its influencing factors, in order to improve the pathological diagnosis rate of Crohn′s disease.Methods:From July 2016 to April 2021, at the First Affiliated Hospital of Soochow University, 199 patients who met the clinical diagnostic criteria for Crohn′s disease and underwent endoscopic biopsy were collected. The detection rates of non-caseating granulomas in all patients with Crohn′s disease, in different types (primary and recurrent) and whether the biopsy site included the colon were analyzed. According to whether non-caseating granulomas were detected by endoscopic biopsy, the patients were divided into the detected group and the undetected group. The clinical data of the two groups of patients were compared, which included gender, age, course of disease, body mass index, smoking status, clinical manifestations (abdominal pain, diarrhea, gastrointestinal bleeding, perianal lesions, weight loss, fever, intestinal obstruction), therapeutic medication (5-aminosalicylic acid, immunosuppressants, glucocorticoid, biological agents, exclusive enteral nutrition), history of bowel surgery, laboratory examination results (hemoglobin, platelet count, neutrophil count, C-reactive protein, erythrocyte sedimentation rate, albumin), endoscopic manifestation (ulcer, fistula, stricture), simplified Crohn′s disease activity index (CDAI), total number of biopsy samples, and site of biopsy. Chi-square test, continuity correction chi-square test, Mann-Whitney U test and Fisher exact test were used for statistical analysis, and logistic regression analysis was used to analyzed the influencing factors of detection of non-caseating granulomas under endoscopy. Results:Among the 199 patients with Crohn′s disease, 67 cases were detected with non-caseating granuloma (detected group), and the overall detection rate was 33.7% (67/199); 132 cases were not detected with non-caseating granuloma (undetected group). The detection rate of non-caseating granulomas in patients with primary Crohn′s disease was higher than that of recurrent patients (39.9%, 59/148 vs. 15.7%, 8/51), and the detection rate of non-caseating granulomas in patients with Crohn′s disease whose biopsy site included the colon was higher than that of patients whose biopsy site did not include colon (64.1%, 25/39 vs. 26.3%, 42/160), and the differences were statistically significant ( χ2=9.93 and 20.12 , P=0.002 and <0.001). The age of patients in the detected group was younger than that of the undetected group; the course of disease of the detected group was shorter than that of the undetected group; the proportions of patients with abdominal pain and history of biological treatment in the detected group were lower than those of the undetected group; the simplified CDAI score of the detected group was higher than that of the undetected group; and the total number of biopsy samples of the detected group was more than that of the undetected group (30.0 years old (25.0 years old, 37.00 years old) vs. 32.0 years old (28.0 years old, 41.0 years old); 1.0 year (0.0 year, 3.0 years) vs. 2.0 years (0.0 year, 5.0 years), 61.2%, 41/67 vs. 75.8%, 100/132; 0, 0/67 vs. 10.6%, 14/132; 5.00 (2.00, 7.00) vs. 4.00 (2.00, 6.00); 10 (8, 12) vs. 6 (3, 9)), and the differences were statistically significant ( Z=-2.29, -1.99, χ2=4.56, corrected χ2=6.11, Z=-2.05, -5.64, all P<0.05). The case number of biopsy location in terminal ileum, colon, ileocolon, upper gastrointestinal tract, terminal ileum+ upper gastrointestinal tract, ileocolon+ upper gastrointestinal tract in the detected group was 36, 4, 18, 1, 5 and 3, respectively, compared with those of undetected group (94, 4, 8, 11, 13 and 2), the difference was statistically significant (Fisher′s exact test, P<0.001). The results of multivariate logistic regression analysis suggested that the total number of biopsy samples, whether the biopsy site included the colon and disease type were independent influencing factors for the detection of non-caseating granulomas under endoscopy in patients with Crohn′s disease (regression coefficients=0.157, 0.979 and -0.960, OR=1.171, 2.662 and 0.383; 95% confidence interval 1.067 to 1.284, 1.140 to 6.214, 0.158 to 0.929; P=0.001, 0.024 and 0.034). Conclusions:For endoscopic examination in patients with suspected Crohn′s disease, the total number of biopsy samles should be increased as much as possible, and biopsy should be performed at the colonic lesions, in order to improve the detection rate of non-caseating granulomas under endoscopy thereby providing more pathological evidence for the diagnosis of Crohn′s disease.