Food safety has become a hot topic of widespread concern across society, and efficient, sensitive detection technologies are essential tools for ensuring food safety. Immunoassay is the gold standard for high-sensitivity detection of biochemical targets, providing an excellent platform for the detection of food contaminants. In recent years, it has gradually been applied to various food safety detection methods. Nanoenzymes, as synthetic analogs of natural enzymes, offer advantages such as good stability and high sensitivity, meeting the demands of rapid detection methods under increasingly stringent detection limits. This article reviews the detection principles and advantages of immunoassay technology based on nanoenzyme labeling, discussing its applications in different areas of food safety detection, including agricultural and veterinary drug residues, heavy metal residues, mycotoxins, foodborne pathogenic bacteria, and other harmful substances. It also addresses the future development trends of nanoenzymes.