Based on a single ion model, Hamiltonian of the simplest form about magnetocrystalline anisotropy for Tb 3+ ion was solved by using the numerical method. The relation between the stabilization energy, crystal field coefficient B 2 and the magnetic exchange interaction was studied as temperature approaches to 0 K. The results show that the stabilization energy contributed by Tb 3+ is linear with crystal field coefficient B 2 ° approximately, but it is insensitive to the change of magnetic exchange interaction for the strong magnetic substances such as TbCo 5 , Tb 2 Co 17 and Tb 2 Fe 14 B compounds.