Abstract: Terahertz, as a novel technology, has been widely used in the field of material component recognition, high-speed communication, biomedicine, security imaging and military defense. Various applications of terahertz technology are based on the measurement of terahertz itself and its interaction with substances, therefore the accurate terahertz parameter measurement and relevant magnitude tracing are the technical support and guarantee of terahertz application. The measurement technology and tracing method, developed measuring instruments and devices, and established metrology calibration regulations, and metrology standard device formed in the terahertz radiation parameters metrology standard research by National Institute of Metrology were introduced. The magnitude tracing transitive graphs of terahertz radiation time domain, frequency domain, space domain and intensity were presented, and the measurement uncertainty analysis was carried out. The proposed terahertz metrology method and standard devices can guarantee the reliable magnitude in terahertz technology research and application, and can also provide a reference for other terahertz parameters measurement.