This review summarizes recent advances in the construction and application of multi-step fluorescence resonance energy transfer (FRET) systems based on discrete supramolecular assemblies (DSAs). FRET is a non-radiative energy transfer process that occurs between donor and acceptor molecules, and it has wide applications in light-harvesting systems, bioimaging, optoelectronic devices, and information security. Multi-step FRET systems, which involve sequential energy transfer between multiple acceptors, offer advantages such as larger Stokes shifts, long-range energy transfer, and better mimicry of natural light-harvesting systems. These systems are constructed using various non-covalent scaffolds, including amphiphilic nanoparticles, host-guest assemblies, metal-coordination scaffolds, and biomolecular scaffolds. The use of supramolecular assemblies allows for the self-assembly of donor and acceptor molecules, enabling efficient energy transfer without the need for complex synthesis. The photophysical properties of these systems can be tuned by controlling the donor-acceptor ratios, and the systems can be designed to respond to stimuli such as temperature or pH. Recent studies have demonstrated the potential of multi-step FRET systems in applications such as temperature sensing, photocatalysis, and information encryption. However, challenges remain in the development of these systems, including the need for more diverse energy acceptors and the improvement of system stability. Overall, multi-step FRET systems based on DSAs represent a promising approach for the development of efficient and functional light-harvesting and energy transfer systems.This review summarizes recent advances in the construction and application of multi-step fluorescence resonance energy transfer (FRET) systems based on discrete supramolecular assemblies (DSAs). FRET is a non-radiative energy transfer process that occurs between donor and acceptor molecules, and it has wide applications in light-harvesting systems, bioimaging, optoelectronic devices, and information security. Multi-step FRET systems, which involve sequential energy transfer between multiple acceptors, offer advantages such as larger Stokes shifts, long-range energy transfer, and better mimicry of natural light-harvesting systems. These systems are constructed using various non-covalent scaffolds, including amphiphilic nanoparticles, host-guest assemblies, metal-coordination scaffolds, and biomolecular scaffolds. The use of supramolecular assemblies allows for the self-assembly of donor and acceptor molecules, enabling efficient energy transfer without the need for complex synthesis. The photophysical properties of these systems can be tuned by controlling the donor-acceptor ratios, and the systems can be designed to respond to stimuli such as temperature or pH. Recent studies have demonstrated the potential of multi-step FRET systems in applications such as temperature sensing, photocatalysis, and information encryption. However, challenges remain in the development of these systems, including the need for more diverse energy acceptors and the improvement of system stability. Overall, multi-step FRET systems based on DSAs represent a promising approach for the development of efficient and functional light-harvesting and energy transfer systems.