Lithography is the most important technology when manufacturing of large scale integrated circuit. Since the resolution of a lithographic tool is determined by the performance of the imaging optics. The surface accuracy of lithographic projection objectives is on nanometer scale. It is obvious that the fabrication of such high-quality optics and single lens supporting requires tremendous efforts. In order to design the structure of single lens supporting with high-precision, the surface form of single lens is studied, under gravitational condition. Then, the support structure is analyzed in detail by finite element method (FEM) and a new type of flexible support is presented. Analytical results indicate that the surface figure accuracy of the mirror reach peak valley (PV) of 15.4 nm and root mean square (RMS) of 3.62 nm under the load case of gravity. In order to accept high accuracy for optical surface form analyses by FEM, a new method which could remove the surface form of reference surface and the original surface form of tested surface is built. According to the method, the differences of PV magnitudes and RMS values are only 2.356 nm and 0.357 nm, respectively. The results show that the proposed kinematics mount structures satisfy the mechanical requirements of mounts for 193 nm projection lithographic lens.