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A novel series of color-tunable single-phased phosphors La1–x–yPO4:xEu3+/yTb3+(x=0, 0.01, 0.02, 0.03, 0.04, 0.05; y=0, 0.05, 0.10, 0.15, 0.20) was synthesized via co-precipitation method with diammonium hydrogen phosphate as precipitant. The morphology, crystal structure and photoluminescence properties of the as-prepared samples were characterized by means of X-ray diffraction(XRD), scanning electron microscopy(SEM) and fluorescence spectrophotometer. The results reveal that the as-synthesized samples calcined at 1100 °C display spherical morphology with uniform distribution. Upon excitation with 350 nm ultraviolet radiation, the LaPO4:Eu3+/Tb3+phosphors showed a green light peaking at 543 nm assigned to the characteristic 5D4-7F5emission of Tb3+and a red light peaking at 591 nm corresponding to the characteristic 5D0-7F1emission of Eu3+simultaneously. For the Eu3+/Tb3+co-activated phosphors, Tb3+acts as an efficient sensitizer to enhance the emission intensity of Eu3+ions. The energy transfer mechanism and the emission color tunability of LaPO4:Eu3+/Tb3+have been studied. The results indicate that a color-tunable luminescence(from green to white to red) can be achieved by adjusting the Eu3+/Tb3+doping ratio in the LaPO4host matrix.