Objective To evaluate the value of endoscopic ultrasonography (EUS) in the diagnosis of Crohn's Disease (CD).Methods A total of 436 patients with endoscopically suspected CD underwent EUS and the clinical data of these patients were analyzed retrospectively.Changes of gastrointestinal wall stratification and perienteric complications detected by EUS were documented systematically.The consistency between the diagnosis of EUS and the results of pathology were recorded.Results A total of 297 cases of CD and 139 cases of non-CD were clinically diagnosed,while 277 CDs (including 17 non-CDs clinically diagnosed) and 159 non-CDs (including 37 CDs clinically diagnosed) were diagnosed by EUS.The sensitivity,specificity and accuracy rate of EUS in diagnosing CD were 87.5％ (260/297),87.8％ (122/139) and 87.6％ (382/436),respectively.Dilated vessels in submucosa were detected in 40 patients,fistulae in 13,abscesses in 5 and enlarged lymph nodes in 75.Conclusion EUS can show gastrointestinal wall stratification of CD clearly with high diagnostic accuracy.Meanwhile,EUS can detect extraluminal complications well to help in providing useful information for surgery.