The GB/T 13370-1992 standard specifies a method for the determination of lithium, sodium, potassium and cesium in uranium dioxide powder and pellets by Atomic absirption spectropho-tometry, AAS and Flame emission spectrum. The standard describes in detail the reagents, instrumentation equipment, sample preparation methods and analysis steps required for the experiment, and provides a calculation method for the analysis results. It is suitable for the determination of trace lithium, sodium, potassium and cesium elements in uranium dioxide samples. The determination range is 2~ 20 μg/g. This method is used for elemental analysis by atomic absorption and flame emission method after the sample is acidified and the uranium matrix is separated by TBP extraction Resin.