The invention discloses a perception based insulator recognition and defect diagnosis method. The method comprise the following steps: step (1), an electric transmission line knowledge model is adopted for perceiving multiple parallel line structures of an insulator; step (2), an area where the insulator is located is recognized, an overlapped output area is detected as follows: an overlapped area is combined, and a potential insulator area is corrected to a rectangle in any angle; and step (3), insulator chip-missing defect diagnosis based on blocking characteristic quantity is performed, and the glass insulator self-destruction chip-missing defect is diagnosed by adopting two steps of insulator area blocking and interblock similarity computation. The perception based insulator recognition and defect diagnosis method has the benefits that influence of background on recognition of the insulator area can be effectively precluded, and the accurate rate of insulator defect recognition is greatly improved.