以硝酸镧为原料，在较低温度下用水解沉淀法合成了镧的氢氧化物溶胶，用溶胶－凝胶法制备了超细的氧化镧粉体．通过反应温度、ｐＨ值、超声时间等条件的改变研究了在不同反应条件下形成的溶胶颗粒度的变化规律．运用粒度分析、差热、Ｘ射线粉末衍射、红外光谱、透射电镜等多种分析测试方法对干凝胶的分解过程及最终形成的超细氧化镧进行了分析和表征 Lanthanum nitrate was used as a raw material to synthesize a lanthanum hydroxide sol at a lower temperature and a superfine lanthanum oxide powder by a sol-gel method. The variation of sol particle size formed under different reaction conditions was studied by the change of reaction temperature, pH and ultrasonic time. The decomposition process of xerogel and the formation of ultrafine lanthanum oxide were analyzed and characterized by means of particle size analysis, differential thermal analysis, X-ray powder diffraction, infrared spectroscopy and transmission electron microscopy.