Ophiopogonis japonicus is a famous medicinal plant in China with a long history of medicinal and food origin. It contains various chemical components, such as polysaccharides, steroidal saponins, alkaloids, flavonoids, etc. According to traditional Chinese medicine (TCM) theory, it has the efficacy of moistening the lungs and nourishing the yin, benefiting the stomach by generating fluids, and clearing the heart to get rid of vexation. Ophiopogonis japonicus polysaccharides (OJPs), the critical biologically active macromolecules of Ophiopogonis japonicus, have various bioactivities including hypoglycemia, hypolipidemicity, hepato-protection, regulation of intestinal flora, immune modulation, antioxidant, protective activity against cardiac injury, antitumor, etc., and have been widely used in the traditional medicine field and modern pharmacological research. In this paper, we reviewed the extraction, isolation, purification methods, biological activities, chemical modifications, safety evaluation, and potential applications of OJPs, and made a prospect of their related research to reveal their mechanism of action and expand their application areas, to provide a strong theoretical basis for the further development of OJPs.