The invention discloses a calibration device and method for an online dynamic visual processing system. The calibration device comprises a clamping mechanism, a substrate and a three-dimensional adjusting mechanism. The calibration method comprises coarse calibration and automatic diagnosis calibration. The coarse calibration comprises visual system calibration, machining device calibration and association calibration of a visual system and a machining device. The automatic diagnosis calibration calibrates the precision of correlation calibration through multiple times of positioning calculation, and the time accuracy and the position accuracy of compensation of the machining device are improved. The clamping mechanism and the base plate are used for providing a unified reference for the positions of the camera and the dynamic machining mechanism, the distance between the camera center and the dynamic machining center is accurately measured through automatic diagnosis and calibration,part of links in the calibration process are automated and highly refined, and the intelligent level of the system is effectively improved.