Abstract: Taking the fabrication of a K9 planar part with the diameter of 27mm, accuracy requirement of N=2, ΔN=0.5, B≤Ⅱ and θ≤2′ as an example, the processing flow and key techniques of deformable super-thin planar elements controlled by thicken-optical contact method are described. The parameters in manufacturing process are analyzed and summarized, and the parameters for achieving various specifications are determined. The result proves that this method can meet the requirements of high-precision surface profile and parallelism. The production efficiency was increased and the production cost was decreased while the accuracy of such optical element was ensured. This method is suitable for the mass production.