Abstract: AIM: To synthesize derivatives of 2-deoxy-2,3-dehydro-N-trifluoroacetyl-8,9-disulfoneuraminic acid(Neu5FA2en 8,9-disulfates) and investigste their inhibitory activities towards sialidase. METHODS: Using 2-deoxy-2,3-dehydro-N-acetylneuraminic acid methyl ester(Neu5Ac2en methyl ester) as starting material, barium hydroxide as deacetylation agent, ethyl trifluoroacetate as trifluoroacetylation agent, sulfur trioxide triethylamine complex as sulfation agent, the title compounds were synthesized. RESULTS: Seven derivatives of Neu5Ac2en with N-trifluoroacetyl group and/or N-trifluoroacetyl-8,9-disulfate groups were synthesized, all of them are new compounds. Primary inhibitory test indicated that all compounds showed sialidase inhibitory activities, among them compound (10) showed strongest activity. CONCLUSION: Route of synthetic of introducing N-trifluoroacetyl group and 8,9-disulfate groups to Neu5Ac2en was displayed, and both the groups of trifluoroacetylamino and sulfate in the molecule might enhance the sialidase inhibitory activity.