A new method of on-field calibration of the visual measurement system for seamless steel pipe was presented.According to the on-field working requirements,a new calibration system with suspend-wire target and theodolite pairs was designed.By measuring the lighting points on the suspend-wire target with the vision sensor and the theodolite pairs,the sensor and global calibrations can be achieved at the same procedure.The method experimentlly proven to be simple,lower labour intensity and good maneuverability.The calibration results can be verified easily,the precision is better than 0.2 mm.