A novel supramolecular elastomer based on waterborne polyurethane (WPU) and α-cyclodextrin pseudopolyrotaxane (NPR) exhibits reversible phosphorescence behavior under mechanical stretching. The NPR is formed by threading naphthalene-modified polyethylene glycol (NPEG) into α-cyclodextrin (CD) cavities, which not only induces phosphorescence in the naphthalene group through macrocyclic confinement but also provides interfacial hydrogen bonding between CD and WPU chains, enhancing mechanical properties. The elastomer shows stable phosphorescence (τ = 762.34 ms) in water, high temperatures, and chemical environments, with phosphorescence intensity increasing threefold under 200% strain. This reversible phosphorescence is attributed to strain-induced microstructural changes that inhibit non-radiative transitions and NPR vibrations. The elastomer's phosphorescence is enhanced by the CD confinement and interfacial hydrogen bonding, which stabilize the triplet state and reduce quenching by external factors. The material's unique properties enable applications in information storage and encryption, with patterns stored in the elastomer being readable under UV light on and off. The elastomer also demonstrates excellent mechanical resilience, with reversible microstructural changes upon stretching and recovery. The study highlights the potential of supramolecular elastomers for mechanically responsive luminescent materials, offering new possibilities for applications in sensing, security, and smart materials.A novel supramolecular elastomer based on waterborne polyurethane (WPU) and α-cyclodextrin pseudopolyrotaxane (NPR) exhibits reversible phosphorescence behavior under mechanical stretching. The NPR is formed by threading naphthalene-modified polyethylene glycol (NPEG) into α-cyclodextrin (CD) cavities, which not only induces phosphorescence in the naphthalene group through macrocyclic confinement but also provides interfacial hydrogen bonding between CD and WPU chains, enhancing mechanical properties. The elastomer shows stable phosphorescence (τ = 762.34 ms) in water, high temperatures, and chemical environments, with phosphorescence intensity increasing threefold under 200% strain. This reversible phosphorescence is attributed to strain-induced microstructural changes that inhibit non-radiative transitions and NPR vibrations. The elastomer's phosphorescence is enhanced by the CD confinement and interfacial hydrogen bonding, which stabilize the triplet state and reduce quenching by external factors. The material's unique properties enable applications in information storage and encryption, with patterns stored in the elastomer being readable under UV light on and off. The elastomer also demonstrates excellent mechanical resilience, with reversible microstructural changes upon stretching and recovery. The study highlights the potential of supramolecular elastomers for mechanically responsive luminescent materials, offering new possibilities for applications in sensing, security, and smart materials.