The results of the study on 2253 samples of soil and leaves in Fujian tobacco planting area were summarized as follows: The range of the content of exchangeable magnesium in the tobacco soil was 1.80~256.80mg/kg, and the average of the content was 34.49mg/kg. 88.86% of all soil samples, the content of exchangeable magnesium were lower than 50mg/kg; The range of the content of magnesium in tobacco leaves was 0.06%~1.60%, and the average of the content was 0.24%. 43.00% of the tobacco leaves samples, and the content of magnesium was lower than 0.20%. The contents of magnesium in the tobacco leaves were poor, and rational application of magnesium fertilizer should be paid attention to. A field experiment was carried out, MgO was the better choice of Mg fertilizer for Fujian tobacco planting area; The proper doses of MgO was 75-150kg/hm2 in soil of magnesium deficiency.
