The China Institute of Metrology is affiliated with the General Administration of Quality Supervision, Inspection and Quarantine of China. It is a national high-level metrology research center and a national statutory metrology technology institution, and is a social welfare scientific research unit. The main tasks carried out include comparing the values of measurement benchmarks, measurement standards, and reference materials to achieve equivalence. Carry out domestic value comparison work, undertake the assessment of measurement technology institutions, measurement standards, and capability verification work, and undertake the reliability evaluation of measurement methods and results. Undertake the traceability of measurement values of technical institutions such as the National Quality Inspection Center and State Key Laboratory, and undertake the types of measuring instruments