Abstract: In order to explore approaches for improving severely acidified and insufficient magnesium (Mg) volcano ash soils with tobacco planting in Tengchong, Yunnan province, field experiments were conducted to investigate the effects of various Mg fertilizers on soil pH, nutrient, soil microorganism, and soil enzyme activity. The results showed that application of dolomite powder could increased soil available Mg content 13.07-20.36 mg/kg, reduce soil acidification. The Mg fertilizers can be produced locally at low cost. Therefore, dolomite powder should be recommended to improve soil acidification, instead of magnesium sulfate or quick lime in Tengchong.