Abstract: Firstly,the necessity,preparation and primary design of Wuhan No.1 Rapid Rail Transit Engineering are introduced in this paper.Ssecondly,the guidance of the surveying ensurement system is put forward.Thirdly,the composing and establishment of this system is particularly discussed,which includes four divisions:1) the arrangements and data processing of horizontal controlling network,2) arrangements and data processing of vertical controlling network,3) coordinate computing and laying out of characteristics points,4) surveying and mapping of vertical and horizontal section.At last,precision of this system is especially analyzed,which consists of three parts:1) precision of horizontal controlling network,2) precision of vertical controlling network,3) laying out precision of characteristics points.