Objective To evaluate the role of endoscopic ultrasonography in the diagnosis and preoperative staging of rectum carcinoma. Methods Fifty-seven patients with rectum carcinoma were performed with preoperative endoscopy and endoscopic ultrasonography. And the staging results of endoscopic ultrasonography were compared to that of postoperative pathological assessment. Result Compared with the pathological staging, the endoscopic ultrasonography staging accuracy rate was 78.9% (45/57),and lymph node metastasis accuracy rate was 73.7% (42/57). Conclusion Endoscopic ultrasonography is effective in diagnosing and preoperative staging of rectum carcinoma.