White LEDs have the broad application prospect and market demand, while the red phosphor can greatly affect the color temperature and color rendering index of the modulated white light. In this work, a series of Li ₂Gd _4–xSm _x(MoO ₄) ₇( x= 0.01–0.13) phosphors is prepared by the high-temperature solid phase method. The successful doping of Sm ³⁺into Li ₂Gd ₄(MoO ₄) ₇is confirmed by X-ray diffractometry (XRD) and does not lead to any change in crystal structure. The samples are detected by scanning electron microscope (SEM) to have irregular blocky structures with particle size less than 20 μm. The existence of Li, Gd, Mo, O and Sm elements in the phosphor is confirmed by energy dispersive X-ray spectroscopy (EDS). The observation of X-ray photoelectron spectroscopy (XPS) shows that the activators are successfully doped into materials. Under 406 nm excitation, the emission peaks of the samples are located at 563, 598, 645 and 706 nm respectively, which are caused by the 4f-4f transition of Sm ³⁺, and the strongest emission peak comes from ⁴G _5/2→ ⁶H _9/2transition. It is found that optimal concentration of Sm ³⁺is 0.07. With the increase of Sm ³⁺concentration, the fluorescence lifetime decreases gradually. The temperature-dependent emission of phosphor is also studied. The emission intensity at 473 K is still 79% of that at 298 K, indicating that the sample has excellent heat resistance. The CIE chromaticity diagram shows the luminescence of the prepared phosphor is located in the orange-red region and the color purity is high (99%). Moreover, a white LED is fabricated using the optical doped phosphor, which has CIE coordinates of (0.3788, 0.3134) that are located in the circle of white light. Research shows that the Li ₂Gd ₄(MoO ₄) ₇:Sm ³⁺phosphor is a promising orange-red phosphor for white LEDs.