The topological insulator is a new type of material. The symmetry of crystals plays an important role in both the design of topological insulator and numerical simulations. In order to have a better knowledge to the symmetry,we have to study the crystallography. In crystallography, a point group is a set of symmetry operations, and space groups represent a description of the symmetry of the crystal. In this talk, we use the Hermann-Mauguin notation which is the most common method of naming point groups and space groups. I will review the 1D, 2D and 3D Bravais lattices first. Then I will explain the meaning of every notations in point groups and space groups.