Objective   To evaluate the value of ultrasonic diagnosis of congenital prepyloric diaphragm.     Methods   Twelve cases were collected for the analysis of the characteristics of ultrasonography in diagnosis of congenital prepyloric diaphragm.     Results   Of the 12 cases of congenital prepyloric diaphragm

valvula in pyloric antrum could be observed in 5 cases

inclusive of 2 cases of complicating pachyntic stenosis of pyloric muscular layer. Other valvula in pyloric canal could not be found with ultrasonography. No pyloric muscular layer pachynsis was observed

but signs of pyloric obstruction such as gastric retention

slow or difficult transfer of gastric contents

gastro-esophageal reflux were found. Prepyloric diaphragm was confirmed surgically in all cases.    Conclusion   Ultrasonic diagnosis of congenital prepyloric diaphragm is of practical value in clinical practice and can provide reliable imaging data for the option of preoperative approaches.