Supplementary control point and urban control point have different purpose and characteristic in the view of installation but their measurement method and permanent marker position are very similar. Therefore if we could use them by connecting those two control point, we would improve the arrangement density as well as minimizing cost of restoration from the loss of control point. So we tried to suggest the possibility of connecting these two control point and usage by analysing positional accuracy of urban control point on the base of supplementary control point in this study. The result of this study is as following. When analysing the positional accuracy of 13 urban control points of the study areas, there were RMSE of connection errors between ${pm}8cm$ and ${pm}11cm$ for each measurement point. The result confirmed the possibility of connecting supplementary control point to urban control point and its usage within the allowable error tolerance that the present cadastral law permits.