Objective To study the diagnostic value of miniprobe endoscopic ultrasonography in the diagnosis of colorectal precancerous lesions, and provide reference for clinical prevention and treatment. Methods From January 2016 to May 2017 received 85 cases of colorectal polypoid lesions in patients with colonoscopy examination in our hospital as the research object, and were confirmed by pathological diagnosis, there were 157 polyps like lesions. All patients underwent micro probe endoscopic ultrasonography, the pathological diagnosis as the gold standard were analyzed. Results 157 polypoid lesions, 62 hyperplastic / inflammatory polyp, 81 adenoma, 14 of adenocarcinoma; NBI lesions The contour and surface structure, microvascular morphology definition was significantly better than that of ordinary endoscopy, the difference was statistically significant; NICE typing showed that 157 lesions: 61 lesions were type I, 80 lesions were type Ⅱ, 16 lesions were type Ⅲ; sensitivity and specificity of micro probe endoscopic ultrasonography check the large bowel tumor lesions, the accuracy was 94.7%, 90.3%, 93%; stage compared with the postoperative pathological diagnosis, micro probe endoscopic ultrasonography in diagnosis of colon cancer T staging accuracy rate of diagnosis is 85.7%. Conclusion Miniprobe endoscopic ultrasonography in the diagnosis of colorectal precancerous lesions. High value, can effectively improve the detection rate of colorectal precancerous lesions, with high sensitivity and specificity, accuracy, worthy of promotion.