A calibration method was presented by off-line parameters identification in order to enhance the position measuring accuracy of the Delta mechanism. Based on structure and kinematic model of mechanism, the error sources influenced accuracy of operation end were analyzed. A forward kinematic model contained errors sources was built. By analyzing the effect of error sources on position error of operation end, twelve assembling errors that made more effect on position of operation end were presented and solved, and the forward kinematic model was calibrated. The experiment results showed that the calibrated Delta mechanism improved the measurement accuracy of position.