The skin is the largest organ of the human body and plays a crucial role in providing a protective barrier. Under the long-term assault of various stimuli such as environmental factors, immunity, and genetics, it is prone to barrier damage, which can lead to structural or functional impairments and even result in the onset of skin diseases. Collagen is primarily synthesized and secreted by fibroblasts and is a major component of the extracellular matrix in the dermis. It serves multiple functions, including maintaining the shape of the skin, supporting the structural integrity of tissues, participating in wound repair, regulating cellular behavior, and modulating immune and inflammatory responses. Skin barrier damage is closely associated with the loss of collagen. This article reviews the role of collagen in skin barrier and explores its therapeutic value in treating skin barrier injuries.