The invention provides a bow net state detection method. The method comprises the steps of: A binocular video synchronous acquisition device acquires a first image and a second image of an intersection area of the contact line and the pantograph; obtaining a first image and a second image, aligning the first image and the second image, carrying out stereo matching, obtaining matched correspondingpoints, calculating parallax of the corresponding points to obtain parallax information and a parallax image, then calculating to obtain depth information and carrying out three-dimensional reconstruction, and further obtaining the state of the pantograph catenary. Compared with the prior art, the bow net state can be accurately obtained only by adopting binocular video synchronous acquisition equipment without installing other compensation sensors, such as a laser radar, and the device is simple in structure, low in cost and good in effect. In addition, the bow net state can be continuously and automatically detected through the bow net state detection method and device, the labor intensity of workers can be effectively reduced, and the working efficiency is improved.