Natto is a soybean product fermented by natto bacteria. It is rich in a variety of amino acids, vitamins, proteins and active enzymes. It has a number of biological activities, such as thrombolysis, prevention of osteoporosis, antibacterial, anticancer, antioxidant and so on. It is widely used in medicine, health-care food, biocatalysis and other fields. Natto is rich in many pharmacological active substances and has significant medicinal research value. This paper summarizes the pharmacological activities and applications of natto in and outside China, so as to provide references for further research and development of natto.