BaMgAl10O17:Eu powder was synthesized using a sol-gel process by dissolving BaCO3, Mg(OH)(2)-4MgCO(3)-6H(2)O, EU2O3 and active Al(OH)(3) in citric acid. By tracing the formation process of the sol-gel, it is found that decreasing the amount of NO3- in the solution is necessary for the formation of transparent sol and gel. Results from X-ray diffractionmeter (XRD), thermogravimetry (TG)-differential thermal analysis (DTA) and IR spectra show that BaMgAl10O17 crystallizes completely when the dry gel is sintered at 1300 degreesC. The phosphor particle takes the form of plates if the dry gel is sintered directly, while the particle is more regular when the dry gel is calcined and ground before sintering, and the crystallite size is in the range between 1 and 5 mum. The emission intensity of the phosphor is slightly higher than that prepared by solid-state reaction.