Currently，with the fast development of GPS technique，GPS RTK is rapidly being applied to the cadastral survey． GPS RTK technique not only improves efficiency and accelerates the rate of mapping，but also increases economic efficiency． The authors introduced a method for GPS RTK rapid positioning，which uses continuous operational reference system ( CORS) as a base station to change the method of previous map drawing by obtaining real-time three-dimensional coordinates of boundary points and statistically analyzing with the three-dimensional coordinates obtained by Total Station to get the accuracy of GPS RTK real-time coordinates． The application of GPS RTK in practical measurement was discussed when the data link had been lost especially． The results show that the three-dimensional coordinates measured by total station can be replaced by realtime three-dimensional coordinates measured by Engineering Star RTK in the CORS．