Zero walking amount is one of the important indicators to evaluate the stability of sight. However, when the zero walking amount is measured, the influence of the repeated loading error of sight on the zero walking amount is usually neglected, because the ordinary sight has a low requirement of zero walking. In contrast, in the zero walking amount measurement of a high-precision sight, the repeated loading error cannot be ignored. Based on the principle of self-collimator, a device for automatically eliminating the repeated loading errors is designed, which consists of an automatic laminating device with a semi-reflecting and semi-transmitting and an electro-optical autocollimator. In addition, a pressure sensor is combined with a piezoelectric ceramic transducer (PZT) micro-displacement device to form a micro-motion fine-tuning closed-loop feedback system and the real-time adjustment of the pose of the semi-reflecting and semi-transmitting is realized. Thus the semi-reflecting and semi-transmitting and the end surface of the objective lens are completely fitted. It has been verified by experiments that the device can be used to achieve a measurement accuracy of 2" in the 5° measurement range, which is sufficient to meet the measurement requirements of zero-level reloading errors for a high-precision sight.