Abstract: Sugarcane production is frequently constrained by spring drought, and different genotypes exhibit varied responses to drought stress. This study aims to investigate the prominent physiological characteristics of leaf and root in drought-insensitive sugarcane materials under drought stress and identify key drought-resistance indicators, thereby providing a theoretical basis for breeding drought-tolerant varieties and developing stress-resistant cultivation techniques. Using a drought-insensitive cultivar ‘Yunzhe 05-51’ (YZ05-51) and a drought-sensitive cultivar ‘Yuetang 93-159’ (YT93-159) as test materials, well-watered and drought stress treatments were applied during the early elongation stage. Characteristics related to biomass accumulation, photosynthetic parameters, osmotic adjustment substances, antioxidant enzyme activities, and leaf/root tip ultrastructure were comparatively analyzed. The results showed that under drought stress, the reduction in shoot fresh weight, shoot dry weight, net photosynthetic rate, and transpiration rate in YZ05-51 (40.39%, 30.86%, 38.80%, and 36.25%, respectively) were significantly smaller than those in YT93-159 (52.15%, 50.09%, 52.81%, and 47.22%, respectively) (P<0.05). Meanwhile, under drought stress, the activities of superoxide dismutase (SOD), peroxidase (POD), and ascorbate peroxidase (APX), as well as the contents of proline (Pro), increased significantly in the leaf of YZ05-51, whereas YT93-159 showed opposite trends. In the root of YZ05-51, the activities of SOD, catalase (CAT), and APX increased significantly under drought stress, while they decreased significantly in the control cultivar (P<0.05). Additionally, YZ05-51 demonstrated a stronger capacity to maintain cellular membrane morphology, mitigating drought damage by preserving the structure of chloroplast grana lamellae and the integrity of root cell plasma membranes, while YT93-159 exhibited more severe structural deformation. The drought tolerance of sugarcane results from efficient coordination between root and leaf in antioxidant defense and osmotic adjustment. Comprehensive analyses, including grey relational analysis, indicate that the activities of CAT, POD, and SOD, as well as the contents of MDA and H₂O₂ in both leaf and root, can be used as key physiological indicators for screening drought-tolerant sugarcane materials during the early elongation stage under normal growth condition.