Introduction: Acute abdomen is among the most common causes of pediatric hospitalization and ultrasound is the first diagnostic method. We aim to describe the best method of sonography to find the accurate diagnosis in the least time as possible.
 Materials and Methods:Two independent researchers screened for the articles that were related with acute abdomen and method of sonography in childrens. The electronic databases that were searched including: PUBMED, SCOPUS,EMBASE and WEB OF SCIENCE up to January 2021.
 Results: We search about the common causes of acute abdomen in children that are admitted to the emergency room and we find that if we start the sonography in ileum  terminal and mesenteric vessels in children, so we can diagnosis the etiology in less time and help to manage the critically ill patients in the best way .By identifying ileum terminal in RLQ, appendicitis can be find in posteroinferior of that and  important diseases such as enterocolitis, tuberculosis, Crohn's disease, and lymphoma can be find easily. In epigastric area, diagnosing mal-rotation and mid-gut volvulus is crucial to save a baby's life. complete visualization of the pathway of the mesenteric vessels and visualization of other abnormalities in this area such as HPS, pancreatitis, bowel obstructions.
 Conclusion: systematic sonographic approach in children with acute abdomen can show the main causes، by focusing on the ileum terminal and the mesenteric vessels, and many lesions are seen while trying to find these two viscera. We suggested the main gateways to start the ultrasound examination are RLQ, the terminal ileum, and epigastrium such as mesenteric vessels.