In order to achieve non-contact accurate measurement of the mechanical wear of the elevator traction sheave rope groove, a wear detection system for the elevator traction sheave rope grooves was developed based on monocular vision technology. The industrial camera was fixed on the inner side of the steel wire rope through a special fixture, and the images were collected by aligning each rope groove. OpenCV was used for image preprocessing and rope groove edge detection, least squares method was used for rope groove edge numerical fitting, and then according to the physical model structure, the calculated value was compensated for the occlusion to achieve real-time accurate measurement of the bottoming distance of the wire rope. The experimental results indicated that the RMSE of system measurement is less than 0. 07 mm, the system has higher accuracy and simplicity than traditional manual measurement methods, and can be used to accurately measure the amount of wear and sink of the sheave groove.