Abstract: The method for determining Ca,Mg,Fe and Si in potassium fluotantalate by inductively coupled plasma atomic emission spectrometry was established,with nitric acid and hydrofluoric acid to disolve the sample on ED16 digestion machine.The working parameters of instrument were optimized.Ca 396.847 nm,Mg 279.553 nm,Fe 239.562 nm and Si 251.612 nm were selected as analytical lines.Matrix matching method,background deduction and standard addition method were used to eliminate matrix effect and spectral interference.The results showed that the detection limit of each element was 0.001 3-0.005 9 μg/m L,that the standard addition recovery was 94.4% -106% and that the relative standard deviation was less than or equal to4.19%.The determination results of Ca,Mg and Fe agreed well with those obtained by direct current arc atomic enission spectrometry,and the determination results of Si were consistent with those from methyl green-molybdosiliscic acid spectrophotometry,indicating the method had good accuracy and precision.