By using the irreducible tensor operator method, two corollaries are derived from generalized Wigner-Eckart theorem and the results associated with the corollaries are obtained. For the d2 ions in a trigonally distorted cubic crystal field, we have considered both the interactions of all possible Vc and (Vt+Hs) and taken into account the coval-ent bonding and dynamical Jahn-Teller effects with reduction factors. The groundstate wave functions are obtained through successive perturbations. Then the formulas of g∥, g⊥ and D are derived.In application to vanadium corundum, results in agreement with the experiments are obtained by overall fitting of the theoretical values to the observed values of D, g∥, g⊥ and absorption spectrum.Finally, we discuss the problems involved in our model, methods, results and importance of consideration of all interactions.