Abstract: The widespread application of pesticides is crucial for ensuring the yield and quality of agricultural products. However, the illegal or improper use of pesticides can result in excessive pesticide residues in food, thereby posing a severe threat to consumer health. Currently, the synthesis methods of UCNPs mainly include thermal decomposition, co-precipitation, hydro/solvothermal methods, and sol-gel methods. The modification methods can be divided into hydrophilic modification and targeting modification. Fluorescence detection methods based on UCNPs have been successfully applied to the detection of pesticide residues such as organophosphates, neonicotinoids, pyrethroids, carbamates, and benzimidazoles in food. However, analysis of the specificity and analytical efficiency of these detection methods in actual sample applications reveals that the UCNPs-based detection methods still need further optimization in terms of eliminating interference from complex matrices, simultaneous detection of trace multi-residues, and integration into portable devices. Future research should focus on improving these performance aspects to better provide technical support for rapid pesticide residue detection.