This study investigated the effects of drought stress on seedling growth and leaf photosynthetic physiological characteristics in two species of tung tree (Vernicia fordii and Vernicia montana). A pot experiment was conducted to study the effects of different water treatments (normal irrigation, light drought, moderate drought, and severe drought) on the growth, leaf gas exchange, and chlorophyll fluorescence of two kinds of tung tree seedlings. The results showed that light drought stress did not have any significant effect (P>0.05) on growth, leaf gas exchange, and chlorophyll fluorescence of the seedlings compared to that under normal irrigation. Modest drought stress significantly decreased (P<0.05) tung tree seedlings' chlorophyll SPAD value, growth, net photosynthetic rate (P_n), stomatal conductance (G_s), transpiration rate (T_r), stomatal limitation value (L_s), maximum net photosynthetic rate (P_nmax), light saturation point (LSP), apparent quantum yield (AQY), dark respiration rate (R_d), maximum photochemical efficiency (F_v/F_m), actual photochemical quantum efficiency (Φ_PSⅡ), electron transport rate (ETR), and photochemical quenching coefficient (q_P). Severe drought stress increased intercellular CO₂ concentration (C_i), water use efficiency (WUE), light compensation point (LCP), initial fluorescence (F_o), and non-photochemical quenching coefficient (NPQ) of the seedlings. Under modest drought stress, the decrease in net photosynthetic rate was primarily caused by stomatal and non-stomatal factors of the tung tree seedlings, while the decrease in net photosynthetic rate under severe drought stress was probably due to non-stomatal factors. Our results suggest that Vernicia fordii has a higher photosynthetic activity and efficiency, and a stronger adaptability to drought stress than Vernicia montana.