Abstract: Using N (150 kg/ha) and P (150 kg/ha) as basal fertilizer in dry conditions in a field experiment, the effects of different levels of potash fertilizer (0, 112.5, 225.0 and 337.5 kg/ha) on the growth, nutrient accumulation and quality of Lanzhou lily were studied. The average annual production of one-year, two-year, and three-year old Lanzhou lily increased (52.3±22.7)%, (132.0±52.0)% and (71.3±38.3)%, respectively in response to potassium. Total sugar and crude starch content of Lanzhou lily increased by an average of (4.1±1.92)% and (9.3±5.02)% respectively under potassium fertilizer treatment compared with no potassium fertilizer, while the soluble sugar, crude fiber and crude protein contents decreased (7.9±5.61)%, (7.5±6.91)% and (8.5±5.64)%. There were significant (P<0.05) positive correlations between total sugar and crude starch contents of lily and potassium fertilizer amount, but significant (P<0.05) negative correlations between crude fiber content and potassium fertilizer amount, and a significant (P<0.01) negative correlation between protein content and potassium fertilizer amount. Potassium is one of the main factors that affects yield and quality of Lanzhou lily.