The digital ultrasonic flaw detector is a kind of portable industrial nondestructive testing instrument, which can detect, locate, evaluate and diagnose various defects (cracks, porosity, pores, inclusions, etc.) in the workpiece quickly, conveniently, without damage and accurately. It can be used in the laboratory or in the engineering field. Widely used in boiler, pressure vessel, aerospace, aviation, electric power, petroleum, chemical industry, offshore oil, pipeline, military, shipbuilding, automobile, machinery manufacturing, metallurgy, metal processing industry, steel structure, railway transportation, nuclear power, universities and other industries.