This study aimed to study the effects of drought on biomass and its distribution in a crop of Jerusalem artichoke (JA) under different irrigation gradients and to provide a reference for cultivation and management of the crop in arid area. Drought decreased the organ biomass of both red skin JA and white skin JA. The total biomass, aboveground biomass, and underground biomass under 50% irrigation were significantly greater than those under 10%, 20%, 30%, and 40% irrigation, respectively. The root/shoot ratio of the red skin variety showed a increase tendency with decreases in the irrigation levels, while the white skin variety showed an "up-down-up" pattern. For red skin JA, the root contribution to biomass increased gradually with decreases in irrigation levels, indicating a gradual reduction in leaf, tuber, stem, and petiole contributions. For white skin JA, the contributions of tuber and flower decreased gradually with decreases in irrigation levels, while the contributions of other organs did not display a regular pattern upon changes in irrigation.