This standard specifies a method for the measurement of ultrasonic velocity of materials used in nondestructive testing. This method is mainly used to determine the velocity of ultrasonic propagation inside materials to evaluate their internal defects and structural uniformity. The standard describes in detail the selection of measuring instruments, operation steps and data processing methods to ensure the accuracy and Repeatability of measurement results. This standard is suitable for nondestructive testing of various engineering materials and structures and is widely used in the fields of manufacturing, inspection and maintenance.