Ultrasound technology has been applied in pediatric regional anesthesia. It locates the goal nerve by using the real-time imaging method, and enables the anaesthetists to visualize directly to the various anatomical structures, to observe the needle depth and the spread of local anesthetics when in the implementation of pediatric nerve block, so that it enhances the safety or effectiveness in pediatric nerve block and reduces complications. The article reviews the basic principles of ultrasound technology and the advantages of its application in pediatric regional anesthesia, and also introduces the implementation of ultrasound guidance in pediatric nerve block and the characteristics of ultrasound imaging. The purpose is to provide reference for the application of ultrasound guidance in pediatric regional anesthesia.