Yantai Great Wall Test Co., Ltd. is a third-party non-destructive testing and materials laboratory based in Yantai, Shandong Province, serving the shipbuilding, ship repair, marine equipment, power generation and petrochemical sectors along the Bohai and Yellow Sea coast. The laboratory operates under a documented ISO/IEC 17025 quality system and has been accredited by the China National Accreditation Service for Conformity Assessment (CNAS) and by the Shandong Provincial Bureau of Quality and Technical Supervision under the CMA scheme. The technical scope covers conventional and advanced non-destructive examination including ultrasonic testing, magnetic particle testing, dye-penetrant testing, radiographic testing and ultrasonic thickness gauging, supported by mechanical performance testing, chemical analysis, failure analysis, metallographic examination, dimensional measurement and environmental simulation testing. Marine work includes hull and machinery NDT during ship-repair periods at Yantai, Penglai and Longkou yards, class-related thickness measurement campaigns on bulk carriers, tankers and offshore units, weld examination on new construction blocks, and class-accepted underwater hull inspection coordinated with diving partners for in-water surveys. Great Wall Test is recognised by DNV as a service supplier for marine non-destructive examination under the DNV402B scheme and is also approved by ABS for the corresponding NDT scope, allowing reports issued at Yantai to be used directly for class surveys and statutory inspections on tonnage flying flags that recognise these IACS members. NDT technicians hold Level II qualifications under recognised certification schemes such as ISO 9712 or SNT-TC-1A, and equipment is calibrated against traceable reference blocks before each campaign. Reports are issued in IACS-aligned formats with traceable inspector signatures, photographic evidence and clear acceptance criteria so that class surveyors can review and witness the work directly without rework.