Abstract: Basic principle of three-axis high-resolution MFL internal inspection technology is introduced, differences of this technology with conventional MFL internal inspection technology are compared and signal indications located in the defects examined by the technology and application characteristics of the technology are analyzed.Combined with actual inspection case, defects and signal indications detected in metal loss, metal increase, girth weld defects and spiral weld defects and so on are analyzed, and practicability and superiority of this technology are discussed.