Double grafting is an innovative horticultural technique that enables the rapid and cost-effective development of ideal plants by incorporating an interstock between the scion and rootstock. This review comprehensively examines the multifaceted impacts of double grafting on plant physiology and development. This includes how double grafting influences the plant healing process, photosynthetic efficiency, nutrient uptake and transport, phytohormone regulation, and gene expression. Furthermore, we analyze and synthesize the roles of double grafting in promoting dwarfing, regulating bud differentiation, enhancing stress tolerance, and improving overall yield and quality. By integrating insights from both fundamental research and practical applications, this review aims to provide a forward-looking perspective and a robust theoretical foundation for the global advancement of double grafting technology.