Comprehensive capacity assessment is the premise that ensures potential suppliers should provide high quality domestic materials/standard products, and is important for building quality engineering of China's civil aircraft materials/ standard products, as well as the localization of civil aircraft industry. Through comprehensive capacity assessment---including engineering, quality, airworthiness and special processing---for the potential suppliers' materials/standard products, and on the base of passing product qualification testing, we conduct on-site inspection and evaluation for the above capacities. The products of potential suppliers should be included in Qualified Product List (QPL) for civil aircraft development after accepting our recommendations for improvement.