The airflow characteristics impacted on the drought areas were analyzed with V-3θ plot which revealed characteristics of the atmospheric thermal structure. The relationship between the atmospheric thermal structure and the variation of earth rotation (length of day, nutation, polar motion) was analyzed with the update data of IERS. Based on the total momentum conservation of earth and atmosphere, the variations between the atmospheric thermal structure and the earth rotation were restricted to each other. The research results showed that large scale drought was related to the air path change caused by characteristics of atmospheric structure and the earth rotation.