Abstract: The composition of metallocene catalyst was complex. The effects of major elements on potassium, calcium, sodium and magnesium were investigated. The result showed that aluminum and titanium had more serious chemical interference on the determination elements, and the interference was eliminated by adding release agents La and Sr. The types and amount of release agent were also investigated. The samples of metallocene catalyst were prepared by wet digestion, and the potassium, calcium, sodium and magnesium in the catalyst were determined by atomic absorption spectrometry. The calibration curve correlation coefficient of each element is greater than 0.999, and the detection limit is less than 0.03 μg/mL. The precision and accuracy of the sample were also investigated. The relative standard deviation of the result was less than 2%, and the recovery rate was 95%-104% within determining concentration scope of each element.