In order to construct monitoring and evaluation indexes of tobacco drought disaster in Guizhou region, a linear regression equation was established for the water deficit rate and yield reduction rate of Guizhou tobacco during different growth periods. According to the classification criteria of agricultural drought grade, the drought indexes of tobacco during different growth periods were obtained. The results indicate that when the ranges of the water deficit rate in the whole period were ≤15%, (15%，35%］, (35%，55%］ and >55%, light drought, moderate drought, severe drought and extreme drought occurred, and the corresponding reduction rates were ≤10%, (10%，20%］, (20%，30%］ and >30%, respectively. When the ranges of the water deficit rate in the flourishing period were ≤35%, (35%，70%］ and >70%, light drought, moderate drought and severe drought occurred, and the corresponding reduction rates were ≤10%, (10%，20%］ and (20%，30%］, respectively. When the ranges of the water deficit rate in the maturing period were ≤35%, (35%，75%］ and >75%, light drought, moderate drought and severe drought occurred, and the corresponding reduction rate were ≤10%, (10%，20%］ and (20%，30%］, respectively.