In rocky regions affected by desertification, prominent problems of thin soil, destruction of arid vegetation, and ecological deterioration present a big challenge to afforestation. Artificial recovery of forests is a quick and effective approach to restore the ecology of a region. Pot seedlings weight and Li-6400 photosynthetic system measuring method were adopted to study water consumption and photosynthetic characteristics under drought stress in Machilus leptophylla, Liquidambar formosana, and Michelia fulgens. The results were as follows: (1) The net photosynthetic rate (Pn), stomatal conductance (Gs), transpiration rate (Tr), and intercellular carbon dioxide concentration (Ci) declined in the three karst species. During severe drought, photosynthesis and water use efficiency of Machilus leptophylla were 2.5- and 89.6-fold higher than those of Liquidambar formosana and 1.9- and 26.3-fold higher those of Michelia fulgens, respectively. (2) Drought stress in the middle and late growth season decreased leaf Pn and Gs in Liquidambar formosana and Michelia fulgens but increased the Ci, suggesting that non-stomatal limitations contributed to the decrease in Pn. (3) The total water consumption and daily average water consumption rate of the three species showed significant differences (P < 0.05). The daytime water consumption was 74%-92% of the total daily water consumption. Machilus leptophylla showed a high demand for water with a relatively high water consumption rate that was 3.7- and 2.2-folds higher than that of Liquidambar formosana and Michelia fulgens. (4) Diurnal variation in water consumption rate showed a single peak curve in all three tree species, and the peak changed under different drought stress. (5) Over all, Machilus leptophylla and Liquidambar formosana are species with relatively high photosynthetic rate and water use efficiency. The subordinate function results showed the drought resistance ability in the following order: Liquidambar formosana > Machilus leptophylla > Michelia fulgens, under normal, mild, and severe drought stress conditions, and Machilus leptophylla > Liquidambar formosana > Michelia fulgens, under severe drought stress.