Many of the purine pyrimidine nucleoside analogues, which are promising antiviral compounds, are antiviral in tissue culture and in vivo. The compounds with selective inhibition of the virus, low toxicity, and effective in animals develop into nuclei Glycosides antiviral drugs. Currently, nucleoside drugs that are effective in clinical applications, have commodities, and have been recognized include iodine glycosides, trifluorothymidine, cyclosine, a sugar adenosine, acyclovir and so on. Nucleoside drugs that have a certain effect in clinical trials, have goods in some countries, yet to be recognized include ribavirin, arabinosyl adenosine monophosphate, bromide uridine and so on. Clinical trials are under way to observe the effect include fluoro-iodine cytosine. The new anti-viral nucleoside compounds have been reported is still in research and development. Nucleoside analogs are nucleic acid antimetabolites that are structurally analogous to nucleic acid precursors, competing for nucleic acid synthase enzyme systems, replacing normal nucleic acid precursors, or inhibiting nucleic acid synthetases, blocking viral or cellular nucleic acid synthesis, selectively inhibiting viral nucleic acids , while have little effect on the synthesis of nucleic acid.