Symptoms appear 3 to 6 weeks after birth, or earlier, and rarely occur after 4 months of age. Vomiting is the main symptom, initially only reflux, followed by jet vomiting. Vomiting is occasional at the beginning, but as the obstruction increases, vomiting occurs after almost every feeding. The vomit is mucus or milk, and if it is retained in the stomach for a longer period of time, it vomits curds without bile. In a few cases, due to irritable gastritis, the vomitus contains fresh or denatured blood. After vomiting, the infant still has a strong appetite for food and can still suck hard if fed again. In immature infants, the symptoms are often atypical, and the ejection of vomit is not significant. As vomiting increases, weight does not increase at first due to insufficient milk and water intake, then decreases rapidly, urine output decreases significantly, and the infant passes stool once every few days in a small and hard volume, with significant loss of weight, loose and wrinkled skin, reduced subcutaneous fat, and a depressed and distressed appearance. Vomiting at the beginning of the disease and losing a lot of gastric acid can cause alkalosis, shallow and slow breathing, and laryngospasm and hand and foot convulsions, etc. The most reliable diagnosis is based on palpation of the pyloric mass. If the mass cannot be palpated, real-time ultrasonography or barium meal can be performed to help clarify the diagnosis. After active adjustment of the internal environment, surgery is performed as early as possible with definite surgical efficacy, and laparoscopic completion of this type of surgery is now very mature.