Elevated CO 2 and nitrogen (N) supply enhance plant drought tolerance, yet their interactive effects on leaf hydraulic-photosynthetic coordination remain unclear. Here, we investigated how CO 2 enrichment and N application regulate stomatal behavior and leaf anatomy to optimize drought adaptation in tomato ( Solanum lycopersicum L.). Field experiments combining CO 2, N, and drought treatments revealed that leaf transpiration decreased nonlinearly with declining root water potential, while elevated CO 2 and N significantly improved leaf water potential and gas exchange. Anatomical analyses demonstrated that stomatal density and chloroplast structure jointly mediated hydraulic conductivity and photosynthetic efficiency. Structural equation modelling suggests that increased CO 2 and N application can mitigate hydrodynamic properties and photosynthesis in tomato under drought stress by modulating leaf stomata and anatomy. These findings highlight the critical role of leaf anatomical plasticity in coordinating hydraulic and photosynthetic responses under combined abiotic stresses, providing mechanistic insights into crop adaptation to future climate scenarios.