Abstract: The effects of N applied levels of 90kg/ha, 120kg/ha, 150kg/ha, 180kg/ha on the potassium contents of tobacco leaves were studied. The results showed that:1) the potassium contents of tobacco leaves was increased with enhancing the levels of N applied, and gradually decreased with higher stalk position. 2) in range of N rates from 90kg/ha to 150kg/ha, the yields and quality of flue-cured tobacco could be increased with higher nitrogen levels; and over 150kg/ha, the quality was significantly decreased. 3) the supply of potassium in soil wasn't main reason for low potassium contents of flue-cured tobacco leaves in Yunan.