Abstract: The potassium contents in 5 tobacco samples were determined with AAS and FIA-LSP (flow injection analysis-light scattering photometry),respectively.The results indicated that:1) the scattering intensity produced by potassium tetraphenylboron precipitated in basic medium was higher than that precipitated in acid medium;2) the maximum scattering intensity was obtained at the wavelength of 420 nm,and the intensity linearly positively correlated with potassium concentration within the range of 10-60 mg/mL;3) the recovery of potassium was over 90.70% with coefficient of variation under 3.17% at the detection limit of 0.547 mg/mL;and 4) there was no significant difference between the results determined by AAS and FIA-LSP.FIA-LSP is suitable for rapid analysis of potassium in tobacco.