In recent years, up-conversion luminescent materials have received increasing attention because of their excellent luminescence properties in various fields such as biology, chemistry, medicine, and lighting. According to research reports, studies on up-conversion luminescent materials have mainly focused on fluorides, oxides and other substrate materials that usually exhibit relatively poor physical and chemical stability, so the selection of substrate materials with closely matched lattice and dopant ions is the key to achieving high efficiency in up-conversion luminescence. In this paper, Na₂Zn₃Si₂O₈: x%Er³⁺, y%Mg²⁺ orange-red phosphor was successfully prepared by the high-temperature solid-phase method using Na₂Zn₃Si₂O₈, which is a silicate with stable physical and chemical properties, as the main matrix and Er³⁺ ions with rich energy level structure as the activator. The effects of the alkali metal ion Mg²⁺ on the up-conversion luminescence of Na₂Zn₃Si₂O₈: x%Er³⁺ phosphors were analyzed by a series of characterization tests, including crystal structure, X-ray Diffraction (XRD) and Rietveld refinement, up-conversion emission spectra, Fourier Transform Infrared Spectra (FT-IR), variable temperature emission spectra, monochromatic analysis, Chromaticity Coordinates (CIE), Color Temperature (CCT) and Color Purity (C_p). Na₂Zn₃Si₂O₈ belongs to a trigonal structure with space group P1(1) and cell parameters of a=0.512 4 nm, b=0.883 nm, c=1.350 4 nm, α=72.59°, β=101.76°, γ=89.11°, v=0.568 8 nm³, and can provide a good crystal field environment for the luminescent center (Er³⁺). The XRD and Rietveld refinement results show that the doped ions Er³⁺ and Mg²⁺ successfully replace the lattice positions of Zn²⁺ ions with similar ionic radii under the synthesis conditions of 950℃/180 min. The doping of alkali metal ions Mg²⁺ does not cause the formation of spurious peaks or secondary phases, which further proves that the synthesized phosphor is a pure phase structure. The refinement factor further proves that the synthesized phosphor is a pure phase structure. The characteristic green and red emission of Er³⁺ ions in the Na₂Zn₃Si₂O₈: x%Er³⁺, y%Mg²⁺ series phosphors can be seen in the upconversion emission spectra under 980 nm excitation, and the concentration burst phenomenon occurs at the doping concentration >3%. The concentration burst between adjacent Er³⁺ ions is caused by electric quadruple-electric quadruple (q-q) interaction; the doping of Mg²⁺ ions enhances the characteristic emission peak of Na₂Zn₃Si₂O₈:3%Er³⁺ at 661 nm by a factor of 16. The weakening of the absorption peaks in the Fourier Transform Infrared Spectra (FT-IR) spectra can prove that the Na₂Zn₃Si₂O₈:Er³⁺ and Mg²⁺ series phosphors are pure phase structures and the reason for the enhanced luminescence. To further demonstrate the thermal stability of the synthesized phosphors, the emission spectra were analyzed in the range of 25℃ ~250℃. It is found that when the detection temperature reaches 150℃, the integrated intensity of the emission peaks of Na₂Zn₃Si₂O₈: Er³⁺ and Mg²⁺ phosphors at 661 nm is 73.68% of that at room temperature (25 ℃), and the peak intensity of the emission peaks is 66.63% of that at room temperature (25 ℃). This indicates that the phosphor has good thermal stability of luminescence. Finally, the monochromaticity (S_gr) and CIE coordinates of the green and red emission of Na₂Zn₃Si₂O₈: Er³⁺, Mg²⁺ series phosphors were analyzed. It is found that the orange-red emission (S_gr≈-1) of the phosphor at different temperatures is consistent with the CIE coordinates, and the CIE coordinates are close to the standard red emission coordinates (0.67, 0.33), and the color purity reaches 71.45%. The optimized Na₂Zn₃Si₂O₈: Er³⁺, Mg²⁺ series phosphors have good luminescence efficiency, good luminescence thermal stability and color temperature, which are useful for the exploration of high-efficiency orange red up-conversion luminescent materials and solid-state lighting.