Abstract: Rice lodging poses a significant threat to yield stability. With ongoing global warming and the widespread adoption of water-saving irrigation techniques, a critical knowledge gap exists regarding how these two key factors interactively affect lodging. This study aimed to investigate the combined effects of all-day warming and mild alternate wetting and drying irrigation (AWD) on the mechanical strength and lodging of rice stems. A field experiment was conducted utilizing a Free-Air Temperature Increased (FATI) system to simulate future warming conditions. The study employed a split-plot design, with temperature treatments assigned as the main plot factor and irrigation methods as the sub-plot factor. The temperature treatments consisted of 2 levels: ambient temperature (AT) and all-day warming (AW), which aimed to maintain a target canopy temperature increase of 2℃ above the ambient level. The irrigation methods included continuous flooding irrigation (CF) and AWD. At the yellow ripening stage, measurements were taken on stem pushing resistance, growth indicators (including rice height, fresh weight and center-of-gravity height, etc.), and morphological traits (such as section modulus and dry weight per unit length, etc.) as well as biomechanical properties (including bending moment and breaking strength) of the basal internodes (N3, N4). The lodging index was subsequently calculated. The results demonstrated that both AW and AWD significantly enhanced rice stem lodging resistance (P＜0.05), albeit through distinct pathways. AW significantly increased culm wall thickness by 10.6% and dry matter accumulation per unit length by 13.8%～15.3% in the basal internodes, thereby substantially improving breaking strength by 27.4%～32.0%. Conversely, AW also significantly reduced rice height, fresh weight, center-of-gravity height and the resulting bending moment (P＜0.05), contributing to a more compact plant architecture. In contrast, AWD did not significantly alter culm wall thickness but effectively increased the outside diameter of the internodes by 3.0%～7.2%, resulting in a significantly larger section modulus (by 15.3%～16.2%). Furthermore, AWD significantly enhanced the pushing resistance of the intact plant by 25.7%, indicating improved root anchorage. The study revealed a significant interaction between AW and AWD on key parameters of lodging resistance. Regarding pushing resistance per stem, the positive effect of AWD was diminished under AW conditions. More importantly, for the lodging index, the significant reduction (by 24.4%～34.9%) induced by AWD under AT, however, became statistically non-significant under AW. This indicates that the efficacy of AWD in improving stem mechanical strength was attenuated when combined with AW. This antagonistic interaction manifests as an "effect saturation" phenomenon. Potential explanations for this phenomenon may include the genetic potential limitations of the experimental cultivar or competitive physiological responses between the two factors. This suggests that the lodging resistance benefits provided by AWD are temperature-dependent, and future warming scenarios could partially mitigate the marginal gains of AWD in enhancing rice lodging resistance. The study underscores the necessity of considering such interactions when evaluating and optimizing agronomic practices for climate-resilient rice production.