IATF16949 covers a wide range of processes and requires the organization to meet its stringent standards in quality management, supplier management, product development, production, logistics, and after-sales service. The specific content lays more emphasis on defect prevention than ISO9001:2015, that is, attention is paid to reducing quality fluctuations and waste easily produced in the auto parts supply chain. Also, the certification has a built-in PDCA cycle, which can urge the internal process to continue to carry out "adaptive learning" and continuous optimization. Therefore, the operation of the IATF16949 system can effectively prevent product defects, reduce the generation of unqualified products, and truly achieve cost reduction and efficiency.