The method of welding the metal stud or some other metal parts such as bolts and screws to the workpiece is called stud welding.Furthermore,the bolts to be welded are known a s weld studs.Welded studs have been extensively used in automobile manufacturing industry.Unlike regular stud, welded stud has special external features.After completion of welding,the deviations of the studs′ positions o r attitudes from the standard reference pose will cause the difficult subsequent equipment assembly or even un able to be fulfilled and thereby influence the production efficiency and the reliability of vehicle quality.In order to attain weld studs′ pose parameters with online,non-contact,fast and accurate measurement,a method based on monocular vi sion is proposed.First,a calibrated camera is used to collect the image of stud,and then through edge detection and feature extraction techniques,the coordinates of feature point in the image are extracted.Finally,based on the calc ulation model,position and orientation offset are figured out.Experiment results show that the method is o f high maneuverability and accuracy,the position precision and angle precision are ±0.15mm and ±15′,res pectively, and it satisfies the requirement of online,flexible,fast,and high-precision measurement of weld studs′ pose par ameters in automobile and other manufacturing industries.