1-3 months. In general, the training of external auditor qualification certificate takes 1-3 months, which is divided into two forms: entity class and network class. Physical class training needs about 70 hours of courses, including theoretical study and practical operation. The study contents mainly include the requirements of ISO9000, ISO900 1 quality management, etc. Compared with the physical courses, the training time of online courses is shorter, and it takes about 30 hours to participate in online learning.