Abstract:Several expressions of horizontal displacements have been analyzed. A new idea in which the horizontal displacements are represented based on the new type of geodetic coordinate system is put forward. According to the transformation formulas between the new geodetic coordinate and the geodetic longtude and latitude, the horizontal displacement components along the northern(southern) and eastern(western) direction on the ellipsoidal surface can be expressed with the new system.Taking the length as the coordinate parameter,the geodetic computation can be realized simply and conveniently and the first fundamental form on the ellipsoidal surface is brief in the new geodetic coordinate system, so the planimetric position and horizontal displacements can be expressed in the same type of coordinate system. It would be beneficial to the strain field analysis.