Intussusception is a condition in which part of the intestine and its ligament are snapped into the adjacent intestinal cavity, mostly in a cascade fashion, i.e., the proximal intestine is snapped into the distal intestinal cavity. In pediatric clinical ultrasound diagnosis, intussusception is more common in infants and children. The causes of infantile intussusception are not well understood and may be related to anatomical factors such as long mesentery and high mobility during infancy, and may be triggering factors when dietary changes or diarrhea lead to intestinal dysfunction. Infantile intussusception often manifests clinically as paroxysmal abdominal pain, crying, vomiting and jam-like stools, and some children may have palpable sausage-like masses. Sometimes it is difficult to make a diagnosis by clinical manifestations alone. The abdominal ultrasound is a common examination method, which can assist in clinical diagnosis through the characteristic images of intussusception. In the transverse section of intussusception, it shows “concentric circles” or “target ring” sign, and in the longitudinal section, it shows “sleeve” sign. 2, air enema Before the air enema, a comprehensive fluoroscopic examination of the front and side of the abdomen is performed to observe the intestinal inflation and distribution. After air injection, a dense soft tissue mass in a semicircular shape can be seen at the top of the sleeve, protruding into the colon, forming an obvious cup-shaped shadow at the front of the gas, and sometimes some of the gas can be seen entering the sheath to form different degrees of pincer shadows. The diagnosis is clear while repositioning treatment with pressure is also possible. Diagnosis The diagnosis is established when the child presents with paroxysmal crying and restlessness, vomiting, jam-like bloody stools, and a salami-like mass is palpated on abdominal examination. However, in 10%-15% of clinical cases, the typical manifestations of acute intussusception are lacking when the child comes to the hospital, or only one or two of the symptoms are present. At this time, we should carefully check whether the mass can be palpated in the abdomen, whether there is a feeling of emptiness in the right lower abdomen, and observe whether there is jam-like mucus stool on the finger sleeve by anal finger diagnosis, so as to further confirm the diagnosis. If necessary, do abdominal ultrasound and other auxiliary examinations to assist in the diagnosis. Ultrasound examination can make up for the lack of clinical diagnosis. Because of the thin abdominal wall in children, when the abdomen is scanned with a high-frequency probe, the intestinal masses appear as “concentric circles” in the transverse section and “sleeve” in the longitudinal section, which have characteristic performance. Color Doppler flow imaging can reflect the blood circulation status of the intestinal cavity, which can provide the basis for clinical selection of different treatment plans. Ultrasound examination is easy, quick, non-radiological, non-invasive, repeatable, followable and low cost, and has a high diagnostic accuracy, so it is the first choice of examination method for infant and child intussusception.