The invention discloses a detection device for geometric parameters of a contact line. The detection device includes a camera module (1), a light source module (2), a synchronous control unit (3) anda sensor (4). The camera module measures the geometric parameters of the contact line by employing a stereoscopic vision mode, each of linear array cameras is arranged at different positions on the same plane, and the spatial range of contact wires is separately covered with viewing fields of each of linear array cameras. A work mode of the light source module is synchronous strobe, the camera module and the light source module are synchronously triggered by a same pulse signal, and synchronous exposure of a camera and synchronous stroboscopic illumination of the light source are achieved. Thecamera module and the light source module are arranged in a line shape, and beam strongest sections formed by the LED light source module are in a same plane with linear array camera imaging chips. Advantages of the detection device are that the geometric parameters of the contact line are measured by employing the stereoscopic vision mode are measured by stereoscopic vision, and the detection precision is high; and the LED synchronous stroboscopic illumination mode is adopted, the brightness of fill-in light is high and uniform, the image quality is significantly improved, and power consumption of a system is greatly reduced.