Abstract: The impact of pesticide and veterinary drug residues on food safety and human health cannot be ignored, and it is particularly important to develop effective testing technology. In recent years, upconversion nanoparticles (UCNPs) have rapidly become a research hotspot in the field of food safety detection due to their advantages of long luminescence lifetime, good optical stability, and no interference from the luminescence of various actual samples themselves. In this paper, the luminescence mechanism, preparation method and sensing mode of UCNPs are reviewed, and the applications progress of UCNPs in the detection of pesticide and veterinary drug residues in food also is summarized. In addition, the current problems are summed up, and research trends in the future are prospected, aiming to provide reference for food safety detection.