At present, there are almost no specific drugs for coronavirus therapy. Researchers have been working to inhibit growth of the virus, but the virus may mutate and develop resistance to these therapies [1,10]. It is urgent for the international medical community to develop targeted, high-efficiency and low-toxic drugs to treat the coronavirus based on the structure and property of the coronavirus. Polysaccharides have been used in traditional Chinese herbal medicine for at least 500 years [11], and have advantages of wide sources, low toxicity, good biocompatibility, and immune regulation [12,13]. Some polysaccharides, such as carrageenan, chitosan, fucoidan, and astragalus polysaccharide (APS), have been reported to show strong antiviral activity [[14], [15], [16], [17]]. In particular, sulfated polysaccharides can interfere with the entry process of virus by blocking the positive charge of the pathogen surface receptors, to prevent them from binding to heparan sulfate proteoglycan (HSPGs) on the surface of host cell [18]. Thus, polysaccharides are attractive candidates for developing potential antiviral agents. Here, we summarized and analyzed the antiviral properties, mechanisms, and applications of some polysaccharides and their derivatives in the anti-virus field, aiming to provide a new approach to the development of drugs and vaccines for the treatment of coronavirus, especially for COVID-19.