The invention discloses an on-site and real-time calibration method of the pose relation of an industrial robot and a three-dimensional imager. The method comprises the following steps that: step 1) arobot is driven to pass a translational imager with a fixed pose when being located at different positions under a condition that the rotation parameters of a flange coordinate system remain unchanged, so that the same point of a calibration plate can be scanned a plurality of times, and therefore, first point cloud data can be formed, and the rotation and translation parameters of the flange coordinate system are recorded; step 2) the first point cloud data of the imager are processed, a corresponding center coordinate is obtained through a fitting mode, and calibration rotation parameters are calculated; step 3) the robot scans the same target point a plurality of times with different poses when being located at different positions, so that second point cloud data can be formed, and therotation and translation parameters of the flange coordinate system are recorded; and step 4) the acquired second point cloud data are processed, the center of point cloud is solved, and calibrationtranslation parameters are calculated.