Abstract: The aim of this study was to evaluate the growth and gas exchange characteristics of Jerusalem artichoke (Helianthus tuberosus) at different growth stages in a semi-arid area. The growth phenotype and photosynthetic physiology of Jerusalem artichoke high-yield lines (LZJ004 and LZJ119) and low-yield lines (LZJ018 and LZJ188) were evaluated at different growth stages. The results showed that plant height, internode length, leaf number, and leaf area were greater in high-yield lines than in low-yield lines at each stage. Compared with low-yield lines, high-yield lines showed a 44.94%, 8.26%, 12.11%, and 4.79% increase in corolla diameter, receptacle diameter, ligulate petal number, and ligulate petal length, respectively. The net photosynthetic rate (Pn) of high-yield lines was higher than that of low-yield lines. The water use efficiency (WUE) was also higher in high-yield lines than in low-yield lines, except at the rhizome formation stage, and the WUE of high-yield lines did not vary widely among the different growth stages. The sensitivity of Pn, stomatal conductance, and transpiration rate to changes in vapor pressure difference was lower in high-yield lines than in low-yield lines. During the whole growth period, the high-yield lines of Jerusalem artichoke had stronger growth potential and lower sensitivity to drought stress, which ensured highly efficient formation of underground tubers. This information will be useful to accelerate the breeding of high-yield Jerusalem artichoke cultivars.