Abstract: Rosmarinic acid as a very strong antioxidants exists in rosemary with a high content. It has various biological activities such as anti-biotic, anti-inflammatory, anti-virus and anti-cancer activities. In order to offer more information for large-scale preparation and application, a brief review is presented on the extraction, purification methods. The biological activities of rosmarinic acid,such as antibiosis, antivirus, anti-oxidation, radical-scavenging, anti-inflammatory, immunoregulation, protecting nervous system, anti-radiation, antitumor, inhibition of xanthine oxidase and protection of livers and lungs are particularly discussed.