Disclosed is a method for constructing fluorescent Bombyx Mori silkworm silk irradiated by near-infrared light and its products, comprising: (1) preparing upconversion nanoparticles, and performing surface modification with concanavalin to obtain modified upconversion nanoparticles; (2) uniformly dispersing the modified upconversion nanoparticles in water to formulate an aqueous solution of the upconversion nanoparticles, (3) picking mature mulberry leaves, immersing the mulberry leaves in the aqueous solution system of the nanoparticles, leaching water, and naturally drying the mulberry leaves; (4) after silkworms have grown for a set time, feeding the treated mulberry leaves to the silkworms until the silkworms spin silk cocoons; and (5) collecting the silk, so as to obtain mulberry silk that fluoresces under near-infrared light. The present invention selects upconversion nanoparticles capable of emitting fluorescence under the irradiation of near-infrared light which has stronger penetration, thus has better application in deep tissue imaging.