The diagnosis of Crohn’s disease lacks a gold standard for diagnosis and requires a comprehensive analysis and follow-up observation in combination with clinical manifestations, endoscopy, imaging and pathological histology. Clinical manifestations: The peak age of onset is 18-35 years old, with slightly more males than females. The clinical manifestations are diverse, including GI manifestations, systemic manifestations, extraintestinal manifestations and complications. The systemic manifestations include weight loss, fever, loss of appetite, fatigue, anemia, and growth retardation in adolescents; extraintestinal manifestations include arthralgia, iritis, erythema nodosum, gangrenous pyoderma, and aphthous ulcer. Complications include fistulas, abdominal abscesses, intestinal strictures and obstructions, and perianal lesions (perianal abscesses. Less common are gastrointestinal hemorrhage, acute perforation, and in long-standing cases, cancer. Diarrhea, abdominal pain, and weight loss are common symptoms of Crohn’s disease, and the possibility of the disease should be considered if these symptoms are present, especially in younger patients. Colonoscopy generally presents with segmental asymmetric inflammation of various mucous membranes, with characteristic manifestations of discontinuous lesions, longitudinal ulcers, and a pebble-like appearance. Those with high suspicion of the disease should undergo small bowel endoscopy. CT and magnetic resonance intestinal imaging can be done if available. Intestinal tuberculosis, intestinal leukoencephalopathy, infectious enteritis, ischemic enteritis, drug enteritis, eosinophilic enteritis, multiple rheumatic diseases highlighted by intestinal lesions, intestinal malignant lymphoma, and metastatic enteritis should also be excluded. The common symptoms of this disease should be considered if these symptoms are present, especially in young patients. Colonoscopy generally shows segmental asymmetric inflammation of various mucous membranes, with characteristic manifestations of discontinuous lesions, longitudinal ulcers, and pebble-like appearance. Those with high suspicion of the disease should undergo small bowel endoscopy. CT and magnetic resonance intestinal imaging can be done if available. Intestinal tuberculosis, intestinal leukoencephalopathy, infectious enteritis, ischemic enteritis, drug enteritis, eosinophilic enteritis, multiple rheumatic diseases with prominent intestinal lesions, intestinal malignant lymphoma, and metastatic enteritis should also be excluded.