The development of a lightweight space optics remote sensor with wide field and high resolution is one of the key projects of the researchers. As the traditional approaches couldn't meet the requirements of the project, some modern strategies and methods should be adopted. A high precision, long shaped meniscus mirror is studied in this paper, and its material selection, shape, lightweight strategies, machining method, multi-point support pattern and structure are described. Fused silica or Zerodur is selected as material of the mirror in connection with specific stiffness, dimension stability, machining and cost. An aspherical long shaped meniscus mirror is designed for the optical system. There are rarities of lightweight patterns, i.e. triangular, rectangular, circular and hexagon, and the open hexagon (honeycomb) lightweight pattern is selected with regard to the mechanical and thermal property of the mirror. The mirror should be supported at the edge. With the computer simulation, 6-point flexural support pattern is employed, and the conflict problem between multi- point constraint and freeing the degrees of freedom (DOF) is solved. While the mirror is under the loads (0 gravity at different directions, temperature level exchanging and specified temperature gradient, etc.), the deformation of its surface profile is also acceptable. Finally, the machining method of the mirror is introduced and the allowable assembly error of the mirror set is presented.