Double perovskite KLaMgWO sub(6):Eu super(3+) phosphors were successfully synthesized by an improved sol-gel method using citric acid and polyethylene glycol as complexing agents. The structure evolution and photoluminescence were systematically invested by X-ray diffraction, Rietveld refinement and fluorescence spectra. The structure of Eu super(3+) doped samples was double-perovskite with space group C2/m. Enhanced luminescence properties were gotten by adding 5.0 wt% PEG. Na super(+) with smaller radius was selected to substitute K super(+) in this novel host. With increasing the concentration of Na super(+), the tolerance factors decreased and the structure of BO sub(6) tilted gradually and lowered structure symmetry. Then the emission intensity ratio of super(5)D sub(0)- super(7)F sub(2)/ super(5)D sub(0)- super(7)F sub(1) transition increased and the red emission played the dominate role. Also the emission intensity was enhanced by increasing the concentration of Na super(+). The phosphors showed better color purity with better CIE chromaticity coordinates. Therefore the synthesized phosphors is a potential light conversion red material for light emitting diode.