In view of its specialty and superiority, terahertz (THz) technology has been widely used in biomedicine, information science, public security, quantum research, and space exploration. To guarantee the effectiveness and credibility, all of these applications must be based on the traceable measurement of THz parameters. In this paper, the progress in terahertz metrology, including THz spectroscopy metrology, THz frequency metrology, THz radiometry and THz intensity metrology, is introduced.