A series of phosphine oxide-functionalized polyfluorene derivatives, PFH-PO-40-1 (P1), PFH-PO-20- 1 (P2), PFH-PO-10-1 (P3), and PFH-PO-1-1 (P4), were prepared via a palladium-mediated Suzuki cross- coupling reaction. The structures and purities of all polymers were fully characterized by 1H and 13C NMR, UV-vis and photoluminescent spectroscopy, gel permeation chromatography, and TGA/DSC. Their photoluminescent emission spectra showed single broad peaks at about 445 nm in thin films, as compared to 419 and 440 nm in dilute solutions. The difference might be caused by some degree of aggregation in the excited states of the polymers' main chains. The electroluminescence (EL) properties of these polymers were characterized in devices with a configuration of ITO/PEDOT: PSS/Polymer/Alq3P1, which provided an efficiency of 4.2 Cd/A at 6V.