Abstract: As an emerging disinfection technology, 222-nm ultraviolet C light (222-nm UVC) has attracted considerable research interest due to its potent broad-spectrum antimicrobial properties and potentially favorable biosafety profile. This review provides a systematic examination of the photochemical mechanisms mediating the germicidal effects of 222-nm UVC and comprehensively evaluates the biosafety of this technology, with a particular emphasis on potential impacts on cutaneous barrier integrity and ocular surface tissue. Furthermore, we discuss the risk of ozone generation during 222-nm UVC application and critically analyze recent advances in disinfection protocols and device development. By synthesizing current evidence, this review aims to establish a scientific foundation for the precise clinical implementation of this technology and optimize the balance between antimicrobial efficacy and human safety to facilitate the translational applications of this technology in healthcare-associated infection control and public health emergency management.