The polyhalite[K2MgCa2(SO4)4·2H2O]is a kind of fertilizer resource that has been applied rapidly in recent years. It is rich in potassium，calcium，magnesium，sulfur with wide application prospect in agriculture.The effect of applying polyhalite as part of the root-zone instead of potassium sulfate on kunming flue-cured tobacco was studied.The results showed that in Jinning，Yiliang and Xundian，compared with the conventional fertilization with the same amount of potassium fertilizer，the application of polyhalite increased the yield of flue-cured tobacco by 2.32%～9.64%，the total output value increased by 3.07%～13.6%，and the economic benefit increased by 3.22%～10.4%.Basal application of polyhalite remained stable positive effect in the three sites，while polyhalite as topdressing fertilizer showed better than basal application only in Jining，but basal application was better than topdressing in Yiliang and Xundian.Rational application of polyhalite could increase content of K，Ca and Mg in flue-cured tobacco by 9.53%～26.2%，13.4%～25.2% and 25%～104% respectively.In general，for the tobacco fields in Kunming with lower soil available Ca and Mg content，polyhalite is a good fertilizer that can harmoniously supply K，Ca and Mg to tobacco plant.Root-zone application of polyhalite can not only increase content of K，Ca and Mg in flue-cured tobacco，but also improve the yield and quality of flue-cured tobacco.