Food safety is critical to public health and social stability; therefore, the development of rapid, sensitive, and anti-interference on-site detection technologies has become a core demand at the intersection of analytical chemistry and food science. Fluorescence sensing strategies based on the inner filter effect (IFE) have attracted considerable attention in the field of rapid detection, owing to their distinctive advantages, including the elimination of complex covalent modifications of the fluorescent donor and the direct conversion of signal responses into visually identifiable color changes. The integration of IFE-based ratiometric fluorescent probes with hydrogels to construct next-generation platforms for the on-site rapid detection of food contaminants has emerged as a prominent research hotspot in recent years. This review systematically elucidates the sensing mechanisms of the IFE, outlines the core strategies for constructing hydrogel matrices and ratiometric fluorescence systems, and summarizes representative application cases and practical detection performance of this technology in the detection of food contaminants such as pesticide residues, heavy metal ions, and mycotoxins. Finally, in view of the current practical bottlenecks, including interference from complex food matrices and insufficient long-term storage stability of hydrogels, future directions for technological optimization are prospected. This review is expected to provide practical references for the design of novel probes and the development of on-site food testing products.