Effect of potassium nutrition on the quality and yield increasing of potato in high altitude area was studied by the field trial.The results showed that appropriate K application could increase the number of potatoes per plant and proportion of large and medium-sized tubers and decrease the number of the little ones.Meanwhile the starch,vitamin and protein content of potato were increased.With the increase of K application rate,the tube yield,the percentage of big tubers,net value,the ratio of output to input presented the trend of increases firstly and then decrease.The tube yield and the percentage of big tubers were got when K₂O application rate was 180 kg/hm² but the economic efficiency was not higher.Comprehensive analyzing the yield and economic efficiency,135 kg/hm² was the appropriate of K₂O application.