Skin aging is a complex multi-layered physiological process involving the epidermis, dermis, subcutaneous tissue and skin appendages. It is mainly characterized by slowed epidermal renewal, impaired barrier function, dermal collagen loss, elastic fiber degeneration, subcutaneous fat atrophy and decreased function of skin appendages. To address these issues, modern aesthetic medicine widely uses various energy-based devices such as audio, optical and electrical devices for intervention. Lasers achieve precise targeted treatment of pigment and vascular problems and stimulate collagen regeneration through photothermal effect. Intense pulsed light realizes comprehensive skin rejuvenation using a broad spectrum. Radiofrequency achieves firming and lifting by generating heat through electromagnetic waves. Ultrasound focuses energy on the deep layer to achieve lifting. Cryolipolysis selectively reduces fat using low temperature. These technologies can be combined according to the layers of skin problems to achieve synergistic effect and layered anti-aging. By sorting out the multi-layered physiological and pathological mechanisms of skin aging, this paper systematically elaborates the working principles, treatment layers and clinical applications of mainstream aesthetic instruments such as audio, optical and electrical devices, aiming to provide theoretical basis and diagnosis/treatment ideas for medical aesthetics practitioners.