Metrology is the science of measurement and its application, to realize the unity of units, to ensure the accuracy and reliability of the value. Metrology is related to national economy and people's livelihood, and is the basis for scientific and technological progress, the premise of industrial development, fair trade and the normal conduct of the national economy to ensure. Metrology has become the cornerstone of national governance, is one of the important symbols of national core competitiveness. Metrology and standards, conformity assessment, together constitute the foundation of national quality, defined by the United Nations Industrial Development Organization and the International Organization for Standardization as the three pillars of sustainable development of the future world economy. As standard equipment, video measuring machines and coordinate measuring machines are widely used in various metrology institutes and third-party laboratories for the verification, calibration and testing of product geometry.