| In this paper, crop water deficit index was selected to establish the drought indexes according to the potato growth process. The whole growth duration of potato was divided into four stages, namely sowing to emergence, emergence to branching, branching to flowering, and flowering to maturity. Drought was classified into four grades, including light drought, moderate drought, strong drought, and severe drought. The drought grade indexes were determined for each stage and grade. By using the yield and meteorological data at 26 agrometeorological stations from 1981 to 2015, the monitoring and evaluation index of potato drought disaster derived from the regression model portrayed as linear between the crop water deficit index and the relative meteorological yield and the relative growth height, combined with the classification of crop water deficit index specified in industry standards of China Meteorological Administration. According to the crop water deficit index, the critical index value at four stages of potato was 35%, 25%, 20%, 30% for light drought, respectively; it was 50%, 40%, 35%, 45% for moderate drought, and 65%, 55%, 50%, 60% for strong drought, and 80%, 70%, 65%, 75% for severe drought, respectively. Using the drought situation of 80 potato typical sites in the region from 2016 to 2018 to verify the indicators, the evaluation data of the four developmental stages with the same level and a difference of one grade accounted for 83.33%, 82.92%, 76.25%, and 92.50% of the total data, respectively, indicating that the water deficit index established by the study has good accuracy in judging the occurrence of drought. |