This work begins with a study of the synthesis of multi-color luminescence phosphors, which is followed by a discussion of the temperature sensitivity of AgBi(MoO₄)₂:Yb³⁺/Er³⁺. Uniform and approximately spherical particles of AgBi(MoO₄)₂-based phosphors were prepared by a simple one-step hydrothermal method without adding any surfactant. We obtained a series of rich green, yellow, blue, and white luminescence phosphors by doping Ln³⁺ (Ln³⁺ = Yb³⁺, Er³⁺, Ho³⁺, Tm³⁺) into the AgBi(MoO₄)₂ matrix, and an analysis of various correlative factors was made, especially for the amounts of doping ions. Furthermore, the investigation of the temperature sensitivity of AgBi(MoO₄)₂:Yb³⁺/Er³⁺ revealed that the fluorescence intensity becomes lower with increasing temperature from 323 to 573 K. The fluorescence intensity ratio (FIR) of the two thermal coupling energy levels (²H_11/2, ⁴S_3/2) of Er³⁺ was calculated, and the absolute sensitivity of the obtained phosphor reached a maximum value of 1.32% K⁻¹ at 463 K, as obtained by fitting the FIR as a function of temperature, which is a relatively high level compared with other related materials. This material is expected to be used as a highly sensitive FIR thermometer.