Thermo-sensitive PVA hydrogel marking film containing water-soluble rare earth material

The invention discloses a thermo-sensitive PVA hydrogel marking film containing a water-soluble rare earth material, as well as a preparation method and application thereof. Using water-soluble rare earth material K2Yb0.97Er0.03F5 as a main marker and thermo-sensitive polyvinyl alcohol hydrogel as a carrier of a rare earth solution, the thermo-sensitive PVA hydrogel marking film containing the water-soluble rare earth material releases the rare earth solution in a PVA facial mask within a short period of time in shell temperature to enable the rare-earth solution to permeate into subcutaneous tissue for forming a biological fluorescent mark (the fluorescent mark can appear under the radiation of a 980nm laser device), wherein the fluorescent mark is invisible and cannot be scrubbed with chemical methods and physical methods in a normal state. After lasting for 1-2 days, the fluorescent mark is absorbed by human body and disappears. The thermo-sensitive PVA hydrogel marking film has high concealment, security, the characteristic of quick marking and immobility and can be applied to animal skin marking.