Rare-earth upconversion nanoparticles (UCNPs), which can absorb low-energy near-infrared light and convert it into high-energy ultraviolet or visible light, and have excellent optics of low self-luminescence background, adjustable luminescence color, long fluorescence lifetime and good light stability. In addition, they also have the characteristics of high processability and convenient surface functionalization. Therefore, UCNPs have become the research frontier and hotspot of fluorescent anti-counterfeiting technology, and the application prospects are very wide. In this review, luminescent mechanisms of UCNPs, the advantages and disadvantages of a series of preparation methods are analyzed, as well as elaborate the relevant excellent research achievements in recent years in the field of fluorescent anti-counterfeiting such as labels, patterns, and encoding. Furthermore, the problems and challenges in the application of UCNPs in fluorescent anti-counterfeiting are discussed, and also propose the possible development directions in the future.