In this paper, Yb³⁺/Tm³⁺ co-doped phosphate glass is prepared using a high-temperature melting method, and the effects of Tm³⁺ mole fraction and Te⁴⁺ mole fraction in the glass matrix on the upconversion luminescence properties of the glass are discussed. The absorption spectrum shows that the absorption positions of Yb³⁺ and Tm³⁺ ions in the glass do not interfere with each other at the wavelength of 300?1450 nm. The upconversion luminescence properties of the as-prepared glass samples under 980 nm wavelength laser diode pumping are investigated. The results indicate that Yb³⁺/Tm³⁺ has upconversion luminescence peaks at 476 nm (¹G₄→³H₆), 650 nm (¹G₄→³F₄), and 793 nm (³H₄→³H₆), among which the near-infrared luminescence peak at 793 nm is the strongest. The luminescence intensity at 476 nm is the next highest and the lowest at 650 nm. The intensity of the three abovementioned luminescent peaks can be tuned by adjusting the Tm³⁺ mole fraction and the Te⁴⁺ mole fraction in the glass matrix.