In order to eliminate the measurement error by the distance between optical lens note and rotating center in the close-in photoelectric measuring.A trajectory model of optical lens note turning with the rotating mechanism is built.A calibration method of the distance between optical lens note and rotating center is presented.The trajectory of optical lens note is analyzed with coplanar constraints on optical axis and axis of rotation.A simplified model is obtained，which can satisfy the requirement of real-time processing of embedded systems.The experiment results show that the distance between optical lens note and rotating center precision can reach 0.23 mm by using this method.The close-in high precision photoelectric measurement requirements is basically meet.