A soluble blue-light emitting polymer,Poly(9,9-dihexylfluorene),was prepared by using the oxidative polymerization method．The monomer,9,9-dihexylfluorene,was prepared in a DMSO／benzene mixture with solid KOH as catalyst and the product was purified by chromatography with ethyl ether／n-hexane (5／95) as the eluant．Poly(9,9-dihexylfluorene) was synthesized by chemical polymerization utilizing FeCl3 as an oxidizing agent under argon atmosphere at room temperature for three days．Its structure and properties were characterized by FTIR,1H-NMR,TGA,GPC,UV-Vis and photoluminescence spectra. The experimental results showed that the molecular weight of the polymer measured with GPC was Mw／Mn=27692／24476. The thermal degradation temperature (weight loss 5％) of the polymer was over 400℃ either in air,or in Ar．The polymer was found to be fusible at high temperature and soluble in most common organic solvents,such as chloroform,tetrahydrofuran and dichlomethane. Both in solution and film state,the polymer shows strong fluorescent excitation characteristics．The peak wavelength of its photoluminescence in chloroform solution was around 420 nm excited at 320 nm．The polymer can be processed as film by a solution-casting method and shows unique blue light emitting properties,and may be widely used in electronuminescent devices as blue-light emitting diodes and polymer lasers.