Abstract: To direct potassium fertilization for potato production in Inner Mongolia,the experiment of potassium fertilizer effects on potato was conducted at Damaoqi Inner Mongolia.The result revealed that：on the basis of same amount of nitrogen and phosphorus fertilizer,the agronomic traits and economic benefits of potato are all improved with the application of potassium amount increasing.When the application of potassium amount was 10kg/667m2,the total yield（2378.6kg/667m2）,the weight per hole（0.642kg/hole）,the potato size proportion（5.25）,the water productivity efficiency（9.92kg/mm）,and the economic benefits（2348.6Yuan/667m2） were the highest.