Didecyldimethylammonium chloride (DDAC) is widely used as a bactericidal disinfectant in various fields, including the food industry, animal husbandry, and medical treatment. DDAC is chemically stable and difficult to degrade under natural conditions. With the large amount of DDAC being used, its residue on the surface of objects and in the environment is increasing, which can cause adverse effects to organisms. This study focuses on the hazards of DDAC to organisms, analyses the application of chromatography-tandem mass spectrometry, visual inspection, and biosensors in the detection of DDAC, summarizes the methods of DDAC degradation and the mechanisms, highlights challenges in current research, and provides projections for future research, with a view to providing a reference for reducing the hazards posed by DDAC residues.