The invention discloses an 
overhead line system insulator state detection method based on a 
robust principal component analysis method. An insulator sample 
data set is established according to the acquired images of the 
overhead line system support and suspension device, and a 
Mask-RCNN 
convolutional neural network is adopted to perform target detection and segmentation, and therefore, the positions of insulators in the images can be positioned, and the insulators can be segmented; the minimum external moment of the insulators is calculated according to the positioning result, the inclinationangle is detected, and the obtained picture is rotated according to the inclination angle to obtain a horizontal insulator image; the collected insulator images are 
cut one by one to obtain a single insulator piece 
data set with a fixed 
visual angle; foreground and background segmentation is performed on the insulator sheet 
data set with the fixed 
visual angle; and 
texture feature extraction is carried out on the separated foreground through a 
gray level co-occurrence matrix, texture features of the image are extracted by adopting energy and entropy, weighted summation is carried out accordingto whether the texture features are positively correlated, and a threshold value is set to identify the states of the insulators. According to the invention, detection and rapid positioning of defective insulators, 
dirt and other bad states are realized.