Shandong Provincial Institute of Geology Surveying and Mapping，Ji'nan 250002，China

The high- precision coordinates of reference station can be proposed as the starting points in the lay- out of static GPS control network when the traditional observation model is difficult to achieve the expected accuracy in GPS controlling points observation． Taken the construction of D and E grade GPS control network in Linyi City， Shandong Province as an example， the authors introduce the method of setting up GPS control network based on SD- CORS point observation mode and discuss the accuracy of the control network． It is concluded that the application of point observation mode based on SDCORS in D and E grade GPS control network is completely feasible．