Polymetallic MOFs heterostructural composites enhance their usage in a range of sensing domains by combining two or more different MOFs to produce a new MOF-on-MOF integrated module. As its widespread utilization of flavomycin (Fla), there are currently complications with agricultural residue and the environment, consequently, a highly sensitive, portable technology for identification will be required to handle environmental monitoring in real-time. In this work, the structural characterization and characteristics of the two-layer MOF-on-MOF heterostructure are investigated using the epitaxial growth method. Electrons migrate from the Fe metal center to the organic ligand primarily as a result of hydrogen bonding between Fla and the surface of Fe-MOF and energy transfer amongst the Fe atoms and NH2-MIL-101 (Eu). The synergistic impact of NH2-MIL-101(Eu) and Fe-MOF improves the sensitivity and accuracy of detection, which has a 4.8 nm detection limit, enabling the high sensitivity detection of Fla. Likewise, we put together a handheld sensing platform incorporating aerogel and sensing materials that can meet the expectations of real-time monitoring and multiple actual sample detection, and fluorescent MOFs materials offer an innovative viewpoint on the application of creating flexible sensors, enabling a new method of visualization for food safety and environmental early alerting.