The standard "JB/T 9377-1999 Technical Conditions for Ultrasonic hardness gauges" defines the technical specifications and performance requirements of ultrasonic hardness gauges, especially the equipment used for the measurement of Brinell, Rockwell and Vickers Hardness of metal materials by ultrasonic contact Impedance method. The standard covers the environmental adaptability of the instrument, the test force requirements, the design and manufacturing standards of the indenter, etc., to ensure the Stability and measurement accuracy of the equipment under different working conditions, providing reliable technical support for applications in related fields.