Luminescent fiber with a red thermochromic pigment was prepared via wet spinning. The effects of micro-morphology, phase structure, thermal stability, mechanical property, thermochromism and pigment doping on the reflectivity and luminescent properties of the fiber were investigated. The results show that the spinning process and the addition of pigments do not change the phase structure of rare-earth element luminescent materials in the composite fiber. The fiber is basically stable below 200 ℃. The fiber has good mechanical properties. The doping amount of pigment is negatively correlated to the reflectivity of fiber. Under the standard light source, the fiber is red and white at 25 ℃ and 45 ℃, respectively. Under the ultraviolet-visible light source excitation, the fibers exhibit red and yellow-green color at 25 ℃ and 45 ℃ in the dark, respectively. , The fiber with the pigment addition of 8% has good luminescent property and discoloration effect.