Gd doped lead fluoride crystals were grown by modified Bridgman methods. Under X-ray excitation, their emission intensities peaked at 278nm and 312nm increase with the doping amount of Gd3+ ions, but decrease from the beginning part to the finishing end of the crystallization along the growth direction. The concentration of Gd3+ ions in the PbF2 crystal, analyzed by X-ray fluorescence spectrophotometer, also decreases in the same direction as emission intensity does. The correspondence between Gd content and luminescence intensity of PbF2:Gd crystal demonstrates that the non-uniformity of luminescence intensity results from the in-homogeneous distribution of Gd3+ ions in the crystal. It was found that by co-doping suitable amount of alkali metal ions, such as Na+ and K+, with Gd ion into PbF2 crystal, the difference of luminescent intensities and Gd3+ concentration from the bottom to the top of the crystal become smaller and the transmittance is higher than that of the single doping crystal. Especially, the uniformization effect of Na+ ions is better than that of K+ ions. It shows that the role of Na+ in the PbF2:Gd crystal is eliminating the interstitial fluorine ions formed by the doping of Gd3+ ions and so decreasing point defect content in the crystal.%以X射线荧光光谱分析为手段，测试了用Bridgman方法生长的PbF2:Gd晶体中Gd离子沿生长方向的分布. 发现该晶体在X射线激发下的发光强度与Gd在PbF2晶体中的含量变化均从结晶开始端至结晶结束端逐渐降低，表明PbF2:Gd晶体的发光是不均匀的，这种不均匀性源于Gd离子在PbF2晶体中的分布不均匀性. 通过在PbF2:Gd晶体中掺入一定量的碱金属离子, 可以比较有效地改善Gd离子在PbF2晶体中的不均匀分布，使晶体的发光均匀性和透光率得到明显提高，其中以Na离子的均匀化效果为最好. 推测Na离子的作用是消除了PbF2:Gd晶体中因Gd离子的掺杂而造成的间隙F离子，从而使晶体中的缺陷浓度大大降低.
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