The zinc-based compound crystals, which are composed of zinc-anion coordinate tetrahedrons have two kinds of structure:one is wurtzite and the other is sphalerite.In this article the formation process and the ideal morphology of the sphalerite crystals are studied by calculating the stability energy of the crystal growth unit on the basis of the model of anion coordination polyhedron.The favorable growth unit for the growth of the sphalerite crystal is the tetrahedron.Thus the ideal morphology of sphalerite crystals is tetrahedron.The growth rate of the positive polar plane is different from that of the negative polar plane.It is proved by the calculation that zincoxide crystals are impossible to exist in sphalerite,so are zincsulphide crystals in wurtzite.