Lu3Ga5O12∶Tb3+ phosphors is synthesized by the high temperature solid state reaction, and the effects of substitution of Y3+/Gd3+ and Al3+ for Lu3+and Al3+ respectively on the crystal structures and luminescent properties of the phosphors are investigated. Lu3Ga5O12∶Tb3+ shows pure garnet phase, and the excitation spectrum contains two broad bands called A-and B-bands and some lines assigned to the transitions of Tb3+4f8→4f75d1 and 4f8→4f8, respectively. Under ultraviolet (UV) light, the emission spectrum consists of Tb3 + characteristic emission lines corresponding to 5D4→7FJ and 5D3→7FJ transitions. For (Lu, Y)3Ga5O12∶Tb3+system, with the increase of Y3+, the crystal structure remains with a slight lattice expansion, the red-shift of A-and B-bands occurs, the interval between the two bands decreases, and the intensity of excitation and emission enhances. Similar but more obvious changes occurs in (Lu,Gd)3Ga5O12∶Tb3+system in a range of Gd3+ concentration from 0 to 0.75 with respect to Lu3+. The energy transfer of Gd3+→Tb3+ is observed. For Lu3(Ga,Al)5O12∶Tb3+system, with the increase of Al3+, the garnet phase structure remains with a lattice shrinkage, the red- shift of A- and B- bands occurs, the interval between the two bands increases, and the intensity of excitation and emission improves. The difference in ions radii between the cations, and the change of the crystal field environment Tb3 + caused by cations substitution are the main factors of affecting the properties of the phosphors.