Normal wound healing is a well-orchestrated process of inflammatory response, cell proliferation, and tissue remodeling. However, this orderly and precise process is impaired in chronic wounds. A series of complicated pathogenic factors, including enhanced inflammatory response, poor cell proliferation, restrained angiogenesis, restricted collagen deposition, and infection, contribute to the failure of healing of chronic wound. The application of platelet-rich plasma (PRP) has been explored as a treatment for chronic wounds as it can balance wound microenvironment for promoting wound healing. PRP can modulate the inflammatory mediators, growth factors, and cytokines, etc. to correct abnormal biological events and disorderly molecular environment of cell migration and proliferation, and thus promote wound healing appropriately. Yet, the mechanism of PRP in promoting healing of chronic wound is still not elaborated, and the clinical application of PRP needs to be standardized as soon as possible.