Based on the two-center model, the steady-state nonvolatile two-step, two-color holographic recording performance with low-intensity continuous-wave light for LiNbO3∶Fe∶Mn is studied theoretically. The contributions to the space charge fields from the different electron transfer processes between the deep-trap centers (Mn2+/Mn3+) and the shallow-trap centers (Fe2+/Fe3+) are compared numerically. It is found that the direct electron exchange between the Mn2+/Mn3+ and the Fe2+/Fe3+ levels through tunneling effect dominates the amplitude of the total space charge field. This direct electron transfer process plays a key role in the two-step, two-color holography performance also. In addition, the amplitude of the space charge field of deep-trap centers (Mn2+/Mn3+) dominates the amplitude of the total space charge field is proved theoretically.