In connection with local structure, the g factors of 2E state are studied by using complete diagonalization method （CDM）, with the spinel type crystals ZnAl2Ｏ4:Cr3＋, ZnGa2Ｏ4:Cr3＋ and MgAl2Ｏ4:Cr3＋ as the cases. The slight magnetic interactions, including spin-spin （SS）, spin-other-orbit （SOO） and orbit-orbit （OO） interactions are taken into account in our investigations. Theoretical explanations of g factors of 2E state for ZnAl2Ｏ4:Cr3＋ have been given. The results show that the sign of g‖（E′） for ZnGa2Ｏ4:Cr3＋ should be negative. And the value of g factors of 2E state for MgAl2Ｏ4:Cr3＋ have been predicted. It is shown that, the contributions to g factors of 2E state from slight magnetic interactions are appreciable. Compared with the g factors of ground state, the g factors of 2E state are sensitive to the local structure.