Objective To evaluate the value of high frequency ultrasonography in the diagnosis of acute mesentery lymphadenitis in children.Methods Data of 72 diagnosed cases of acute mesentery lymphadenitis with clinical abdominal pain(abdominal pain group),and of 52 hospitalized cases of other diseases without clinical abdominal pain(non-abdominal pain group)were collected.The numbers and sizes of mesentery lymph nodes in the patients of both groups were observed and compared.Results Patients in the abdominal pain group have comparatively more and bigger mesentery lymph nodes.Conclusion High frequency ultrasonography has a great practical value in the diagnosis of acute mesentery lymphadenitis in children.