With the acceleration of population aging, brain-computer interface (BCI) technology, as an emerging enabler in the field of smart elderly care, is gradually integrating into the daily lives of the elderly, demonstrating vast potential in enhancing cognitive abilities, reconstructing functions, and improving interactions. Based on the characteristics of BCI technology and the physiological, psychological, and social conditions of the elderly, this paper, through a literature review and analysis of typical scenarios, identifies three major risks associated with the application of BCI in smart elderly care: insufficient informed consent and the neural data misuse in ensuring information rights; the threat to the life and health of the elderly posed by invasive technology implantation and subsequent device failures; and the exacerbation of social inequality and the difficulty for vulnerable elderly groups to equally benefit due to uneven technology adoption. After analyzing the causes of these risks, a comprehensive regulatory framework is proposed in three dimensions: ethical, legal, and technological. Ethically, it emphasizes technological-emotional support for the elderly and collaborative governance mechanisms; legally, it advocates for strengthening public law, focusing on national intervention systems and clarifying the boundaries of tort and liability in private law; technologically, it focuses on seeking unified technical standards and a flexible regulatory model. Through this multidimensional regulation, potential risks in the application of BCI technology for smart elderly care will be effectively managed, promoting its healthy, orderly, and compliant development, and ensuring that technological innovations maximize their benefits for an aging society.