Aiming at the problem of low recognition rate of video image of visual over contact system（ OCS）earthing system of connection network due to the interference of human and complex environmental factors

a simplified and improved VGG—16 model for depth network is proposed. Benefit from the transfer learning strategy

good feature extraction ability is obtained

and convolution feature is optimized by sparse automatic encoder（ SAE）

which makes the network sparse

it also improves the recognition precsion and generalization ability

reduces training parameters. The model achieves recognition rate of 92 % on validation set.