本文用热分析的方法─—热重（ＴＧ），差热分析（ＤＴＡ）对十水草酸镧的热分解机理进行研究。提出其热分解过程的五个步骤：＋水物→九水物→二水物→无水物→一碳酸二氧盐→氧化物。在热分解阶段的中间产物（一碳酸二氧盐）用红外光谱和ｘ－射线衍射仪进行了测定。 The thermal decomposition mechanism of lanthanum oxalate decahydrate was studied by means of thermal analysis (TG) and differential thermal analysis (DTA). Proposed five steps of its thermal decomposition process: water → nine water → dihydrate → anhydride → a bicarbonate → oxide. The intermediate product in the thermal decomposition stage (a bicarbonate salt) was measured by infrared spectroscopy and x-ray diffractometry.