Abstract: Respiratory viruses, characterized by high mutation rates and strong immune evasion, remain a significant global public health challenge. Natural products have gained increasing attention due to their multi-target modulation and high safety profiles, demonstrating unique advantages in antiviral, anti-inflammatory, and immunoregulatory applications. Forsythia, a deciduous shrub of the Oleaceae family, possesses medicinal value in nearly all its parts, with flavonoids being among its most prominent bioactive components. This review provides a comprehensive summary of the botanical characteristics and traditional medicinal uses of Forsythia, the composition and structural classification of flavonoids from different parts of the plant, and its clinical applications. Building on the "holistic view" of traditional Chinese medicine, this review primarily discusses the antiviral mechanisms of Forsythia-derived flavonoids in four key aspects: viral targeting, immune regulation, inflammation suppression, and post-viral syndrome.Additionally, it analyzes its clinical application advantages and translational strategies, providing a basis for further development of new natural products and therapeutic drugs in clinical practice.