Abstract: Objective：To summarize the clinical features of ultrasonographic diagnosis of acute mesenteric lymphadenitis in children.Methods：The Japan Aloka alpha 7 high frequency probe was used to examine the child's abdomen by multi-section scanning.The observation was focused on the mesenteric root，and lymph node location and number were recorded;measure internal echo as well as the size and shape;observe the flow distribution and record the resistance index.After anti-infection symptomatic treatment，the patients were reexamined by ultrasound，and the results were analyzed through combination with high frequency ultrasonographic diagnosis.Results：All the patients were accurately diagnosed by ultrasound;54 cases were had abdominal pain as the main symptom.The onset of the disease was more common in children under 7 years old，and more likely to be in winter and spring.The upper respiratory tract infection was a common cause of infection，and after anti-inflammatory and antiviral treatment，all recovered.Conclusion：Ultrasonographic examination of children with acute mesenteric lymphadenitis is a reliable evidence in the diagnosis of the disease，and early discovery and treatment will result in better prognosis.

Key words: Mesenteric lymphadenitis, Ultrasonography, Virus infection, Abdominal pain, Children