Abstract: Due tothe difference betweenWGS-84 and local ornational reference systems, such as BJ-54 (Beijing System of 1954), coordinate transformation is necessary before GPS results are utilized for local engineering control. However, the transformation depends on the accurate national geodetic control points that are usually not enough or not available at all in an engineering field. The feasibility to directly utilize the GPS baseline vectors as the distances on the BJ-54 coordinate without coordinate transformation is proved by computation analysis conducted through out China. The principles to determine the proper baseline vectors are studied and presented in detail.