A series of Lu2-xGdx(MoO4)(3):0.02Eu(3+) (x = 0-2) red-emitting phosphors have been synthesized by the standard solid-state reaction method. Interestingly, the Gd concentration plays a profound role to influence the luminescence property. A conspicuous monotonic increase could be found in the influence of Gd3+ concentration to the emission intensity, and finally Gd-2(MoO4)(3):0.02Eu(3+) exhibits the strongest red light emission with the intensifying factor even reaching 3.04-fold compared to Lu-2(MoO4)(3):0.02E(3+). Careful structural analysis suggested that up to about 80% (x = 1.6) Lu can be substituted by Gd with the same crystal structure of Lu-2(MoO4)(3) being retained, while a higher Gd concentration would lead to it crystallizing in the Gd-2(MoO4)(3) structure. We believe that the variation of crystal structure is responsible for the photoluminescence enhancing process.