Meckel diverticulum is one of the most important causes of small bowel bleeding in children. Reports suggest that ultrasonography can be used as an alternative examination for children with negative radionuclide scanning results or children with atypical clinical manifestations. To evaluate the diagnostic accuracy of high-frequency ultrasound in children with bleeding Meckel diverticulum. We collected the data of children who were admitted to our hospital for the main symptom of bloody stool from February 2006 to December 2017. Ultrasonography was performed in all children. The final diagnosis was confirmed by pathological analysis or clinical follow-up observation. We evaluated the diagnostic performance of ultrasonography according to the final diagnosis. A total of 784 eligible children were enrolled in the study. Presenting symptoms or findings included black and red stool in 528 (67.3%), bright red stool in 51 (6.5%) and obscure or occult bloody stool in 205 (26.1%). Anemia was diagnosed in 489 (62.4%). Ultrasonography diagnosed Meckel diverticulum with a sensitivity of 93.6% (95% confidence interval [CI] 91.0-95.6%) and a specificity of 98.1% (95% CI 95.9-99.3%). High-frequency ultrasound diagnosis of Meckel diverticulum in children has high sensitivity and specificity.