3-Hydroxy-4-chloro-1,8-naphthalic anhydride has been designed and solvent-free synthesized with 1,8-naphthalic anhydride as starting material under microwave irradiation conditions.The result compound has been characterized by 1H NMR,MS and Elemental analysis.All reactive steps have been optimized,good reproducibility and high yield(total yield is 64%)have been obtained.When 3-Hydroxy-4-chloro-1,8-naphthalic anhydride is radiated by ultraviolet light at 249 nm,it emits intensive blue fluorescence.3-Hydroxy-4-chloro-1,8-naphthalic anhydride would be a potential materials for many blue fluorescent organic materials.