Background <p>Diagnosing and assessing Crohn’s disease, which involves only the small bowel, is challenging. This study investigated the clinical value of combining double balloon enteroscopy with endoscopic ultrasound to evaluate this disease.</p> Methods <p>This single-center retrospective study included patients with Crohn’s disease of the small intestine between October 2022 and October 2023. Relevant clinical data were collected. Double balloon enteroscopy and ultrasound endoscopy of the small intestine were performed.</p> Results <p>Among the 50 patients, 10, 34, and 6 had mild, moderate, and severe active phase Crohn’s disease, respectively. Ten patients scored between 1 and 4 points on the modified partial simple endoscopic score for Crohn’s disease (mpSES-CD), 24 scored between 5 and 8 points, and 16 scored more than 8 points. Forty patients had thickening of the intestinal wall (total thickness, 4.14 ± 0.98&#xa0;mm). Submucosal and intrinsic muscle layer thickening was primarily observed. Ten patients were in remission, and all mucosal–submucosal and submucosal–intrinsic muscle boundaries could be distinguished. Thirty-four patients had moderate-phase Crohn’s disease, of whom 26 (76.47%) had distinguishable mucosal–submucosal boundaries, and 28 (82.35%) had distinguishable submucosal–intrinsic muscular boundaries. Of the six patients with severe phase Crohn’s disease, four (66.67%) had distinguishable mucosal submucosal boundaries, and two (33.33%) had distinguishable submucosal–intrinsic muscular boundaries.</p> Conclusions <p>The mpSES-CD and Harvey–Bradshaw Index correlate well. Endoscopic ultrasound can determine disease severity by measuring each bowel wall layer’s thickness and observing the distinction between the layers. This combination of techniques can compensate for the shortcomings in diagnosing the depth of the vertical infiltration of Crohn’s disease using white-light endoscopy.</p>