Abstract: Mileage pile, an important sign of engineering construction, operation and management, is of great significance. Due to the long distance, complex coordinate system, design and construction by section, it is particularly difficult to survey and set mileage piles for the long line project. In view of the above problems, an integrated surveying and setting method of mileage pile adapted to path variation is proposed. This method can calculate the center line coordinates of engineering mileage quickly according to variation of any line or curve path in the long-distance project. Furthermore, it is able to determine the coordinates of mileage pile buried points by calculating azimuth angle of vertical or normal line for the center line and by determining the distance between buried points and center line. This method can solve the problems of inconsistent numbers, inconsistent specifications, deviated coordinates and diversified paths of mileage piles in long-distance project. This method has been successfully applied to the survey of kilometer pile and 100-meter pile in the Middle Route of South-to-North Water Diversion Project, and can be extended to other long-distance projects in highway, railway, municipal works.