In this paper, the energy level splitting of the d orbits of Cr2+(3d4) in tetrahedron crystal field (Td point group) is calculated and analyzed by using the point group theory. In consideration of the static state Jahn-Teller effect, the energy level will farther split. First of all, when the five-dimension reduction representation with the five d orbits wave-functions as the base functions is converted to an un-reduction representation, the energy splitting in tetrahedron crystal field can be obtained. Because of the static state Jahn-Teller effect, the tetrahedron symmetry will distort and transform to tetragonal symmetry, at the same time, Td point group will transform to D2d point group, which makes orbits further split. So the energy splitting in tetragonal crystal field can be obtained when the reduction representation with the split orbits wave-functions as the base functions is converted to the un-reduction representation of D2d point group.