Abstract: Cubic lattice is a common crystal structure. In the teaching of solid-state physics in university，the cubic lattice is usually taken as an example to illustrate the spatial distribution characteristics of isoenergetic surface in the form of static images. However，it is lack of the detail changing of isoenergetic surface with the wave vector k. In this paper，the variation of isoenergetic surface of the s-state electron in cubic lattices with the wave vector k under the tight binding approximation is shown in detail by using the MATLAB program. The superposition，crosssection and extension graphs of the isoenergetic surface are also given visually. These images show that when the wave vector k changes from the center of Brillouin zone to the boundary，the isoenergetic surface changes from a sphere to a spherical-like surface until it breaks and concentrates near the corner of Brillouin zone. These results vividly show the changing of isoenergetic surface and it effectively assists teachers' teaching and deepens students' understanding of solid-state physics.

Key words: tight binding approximation, cubic lattice, isoenergetic surface, Matlab