Cyperus esculentus is widely cultivated in arid regions for its drought tolerance, yet its physiological responses under different cropping systems remain unclear. A pot experiment was conducted to examine how monoculture (C), maize intercropping (MC) and wheat intercropping (WC) modulate drought-induced changes in photosynthesis, osmotic adjustment and oxidative stress under three soil moisture levels (CK, 80% CK and 60% CK). Drought reduced plant height, shoot dry mass (SDM) and photosynthetic performance across all planting patterns, with progressive soil moisture reduction causing declines in net photosynthetic rate (Pn), stomatal conductance (Gs), transpiration rate (Tr) and pigment contents. Clear differences occurred among cropping systems. MC consistently maintained higher photosynthetic capacity, with Pn, Gs and Tr being approximately 40-60% higher than in WC and 15-30% higher than in C under drought. MC also showed smaller decreases in chlorophyll pigments and less reduction in maximum quantum efficiency of PSII (Fv/Fm) and effective quantum yield of PSII (Phi PSII), indicating greater stronger photochemical stability. In contrast, WC intensified drought stress, exhibiting the highest levels of proline (Pro), soluble sugars (SS), malondialdehyde (MDA) and peroxidase (POD). PCA analysis further indicated clear physiological differentiation: MC aligned with photosynthesis-related traits, whereas WC clustered with osmotic and oxidative stress indicators. Overall, maize intercropping was associated with reduced drought-induced photochemical inhibition and oxidative damage, whereas wheat intercropping was associated with stronger stress responses, potentially related to increased competition for shallow soil water. These findings provide physiological evidence to guide the optimisation of intercropping strategies to improve drought resilience in arid environments.