Abstract: With the increasing requirement on dam deformation monitoring due to engineering scale, geographical location and environmental impact, it is urgent to develop a vacuum laser collimation system suitable in severe cold regions. Taking a RCC dam in Xinjiang as an example, the research and development process and application of long distance vacuum laser collimation system were introduced from aspects of the structure and design of Fresnel wave plate, the wave plate repeatedly cutting into the light path, high precision repeated positioning and insulation measures, long distance dimming technology and system fault automatic detection. Engineering practice showed that the precision of the vacuum laser collimation system was high, and the problems of deviation, jitter and deflection of atmospheric laser collimation were solved.