[en] In this paper, a novel upconversion phosphor is reported. Based on XRD and EDS, it is confirmed that the phosphor is monoclinic Gd₂Mo₄O₁₅:Yb³⁺, Ho³⁺ with P21/c space group. The non-radiation decay of ⁵I₆ to ⁵I₇ dominants the depopulation of ⁵I₆, thus the phosphor produces the red upconversion emission with high emission intensity and good color quality, and shows the favorable temperature sensing property. When using non-continuous excitation mode, the temperature sensitivity is determined as 0.0452 K⁻¹. Because the sensitivity is the same at any temperature, the new upconversion material may have greater potential for temperature sensing application than Er³⁺ doped upconverison materials. (paper)