Where a shielddriven tunnel is constructed underneath a pipe culvert, the GPS technology is applied in the horizontal deformation monitoring so as to provide horizontal displacement parameters for the boring of the shield machine, through which the pattern of the horizontal deformation of the pipe culvert resulting from the boring of the shield machine is obtained. On basis of the insitu data collection, the factors that have impact on the data collection quality of the GPS is obtained. By means of installing two suitable benchmark points, the problem of transferring the measured displacement values into displacements in required directions is resolved. Therefore, the GPS technology has been sucessfully applied in the monitoring of the horizontal displacement.