This paper introduces generally the basic principle of GPS, common positioning methods and the development history, describes in detail the concept, basic principle, composition and the realization mode of GPS based on the CORS, with the current situation both at home and abroad presented. Based on the application of CORS in large-scale water transportation and road & bridge projects, this paper summarizes the unique advantages of GPS under the CORS mode in all the stages including the survey and design, construction layout, as well as the check and maintenance, and forecasts its application prospect in the large-scale projects which is characterized by the high accuracy, all-weather operation, multi-function and multi-field.