Objective: The industrial waste from hickory nut shells has historically been underutilized economically. This study explored their high-value utilization， focusing on flavonoid extraction while addressing limitations of traditional methods. Methods: The preparation of binary and ternary low melting solvents was studied， and systematically evaluated their physical and chemical properties such as pH value， viscosity， conductivity， density， and polarity Hydrogen bond formation in the solvents was confirmed by FTIR spectroscopy. The response surface methodology (RSM) was used to optimize extraction conditions. Results: Pyr-Glu(Water) achieved wasthe highest extraction efficiency， yielding 18.63 mg/g of total flavonoids. Under optimized conditions (solid-liquid ratio 1∶19， 48% water content， 550 W ultrasonic assistance at 58 ℃ for 40 min)， the total flavonoid yield increased to 20.537 mg/g， significantly improving extraction efficiency. SEM analysis revealed that Pyr-Glu(Water) effectively disrupted the structural integrity of hickory nut shells， with heating and ultrasonic treatment further enhancing flavonoid release. Additionally， Pyr-Glu(Water) components (glucose and L-proline) were edible primary metabolites， enhancing its applicability in food-related contexts. Conclusion: This study provided a novel approach for high-value utilization of hickory nut shells and highlights the potential of natural deep eutectic solvents (NADES) in green chemistry and natural product extraction.