Well-dispersed and one micron-sized spheres of tetragonal Y/Gd/Dy ternary phosphate have been facilely synthesized via microwave-assisted homogeneous precipitation. The spheres are polycrystalline, and the particle size gradually decreases with increasing Gd3+ content. Excessive doping of Gd3+ leads to the appearance of hexagonal-structured rods on particle surface. The Y/Gd/Dy ternary phosphor exhibits two predominant emission peaks, with a blue one at similar to 483 nm and a yellow one at similar to 575 nm, thus yielding a white light-emitting color. Mainly due to the efficient energy transfer, incorporation of Gd3+ resulted in enhanced luminescence intensity, with nearly a 1000% increase at 575 nm. Because the selective energy transfer from Gd3+ to the F-4(9/2)-> H-6(13/2) transition of Dy3+ takes the dominant role, more remarkable enhanced intensity at similar to 575 nm than that at similar to 483 nm was observed. Enhanced emission intensity, shorter lifetimes, and almost the same CIE coordinates were observed at a higher calcination temperature.