In this paper, we established a method to detect the rubidium in mica using atomic absorption spectroscopy. In our experiment, the effects of the amount of the deionization agent of potassium ion solution, the concentration of hydrochloric acid and the coexistence ions on the determination of rubidium were investigated. Under the selected measuring condition, the detection limit of atomic absorption spectrometry was 0.0365 μg/mL, the relative standard deviation was 0.08%, and the recovery was 101%.