A novel non-target computer-vision based technique for stay-cable vibration measurement using an off-the shelf camera is developed, which can measure stay-cable dynamic characteristics by the analysis of cable vibration video clip. Based on the computer vision theorem, the key points of the technique include camera coefficient calibration, optical analysis and cable displacement reconstruction. To validate the accuracy and reliability of the proposed technique, vibration simulation test of a rigid plastic pipe and vibration measurement test of a stay-cable on a pedestrian bridge are performed. The results show that the proposed approach has the accuracy of vibration measurement with the advantages of non-target non-contact measurement, more flexibility, and low cost, which is compared with traditional sensors.