Tm³⁺/Tb³⁺/Mn²⁺ tridoped phosphate glasses containing different Mn²⁺ ion concentrations were synthesized to explore new white-light-emitting material. Under 355 nm excitation, the CIE coordinates (x=0.328, y=0.337) of the Mn0.10 sample doped with 0.10 wt. % Mn²⁺ are close to the standard equal energy white-light illumination (x=0.333, y=0.333). The quantum efficiency of the Mn0.01 sample is very high (~72.32%). The concentration of Mn²⁺ ions has a great effect on the emission color, and the energy transitions from Tm³⁺, Tb³⁺ to Mn²⁺ become more intense with an increase in Mn2+ ion concentrations. The phenomenon is reasonably interpreted based on the analysis of the luminescence lifetime.