In order to real-time and field nondestructive monitoring the potassium accumulation of flue-cured tobacco in field. Different nitrogen levels was designed and the spatial and temporal distribution and variation of potassium accumulation were studied, the canopy spectral data were also collected to analyze the quantitative relationship between the spatial and temporal distribution of tobacco potassium accumulation and canopy spectral parameters. The results showed that the potassium accumulation in the upper layer is not related to the spectral reflectance except for a few bands. The potassium accumulation in the middle and lower layers is significantly negatively related to the spectral reflectance in the visible light band, while the near-infrared band is significantly positively related. Optimal spectral estimate parameters of each leaf layer potassium accumulation are different. RVI(810,680) is the optimal spectral estimate parameters of upper layer, middle layer, middle-lower layer, and the correlation between DλRed and potassium accumulation of the lower layer, middle-lower layer,the whole plant was the highest. The potassium accumulation spectral estimation model of middle layer, lower layer, upper-middle layer, middle-lower layer and the whole plant are y =-0.002 x2+0.159 x- 0.6531 (R2=0.903**), y = 8.8736x2-4.1032x+0.5164 (R2=0.618**), y =0.0856x1.29 (R2=0.744**), y = 6.6558x2+0.5056x-0.3657 (R2=0.821**), y = 0.2803x0.5774 (R2=0.938**), separately, after verification the model have good stability.Therefore, the estimation model based on spectral parameters could effectively retrieve inversion the potassium accumulation in the middle, lower layers and the whole plant of flue-cured tobacco.