Drought and water scarcity have emerged as critical stress factors threatening crop yields in arid regions, necessitating the exploration of innovative water-saving technologies to enhance water use efficiency and optimize soil microenvironments. Through field experiments conducted from 2023 to 2024, this study systematically analyzed the effects of three mulch film widths (W1: ultra-wide film 4.4 m, W2: medium-width film 2.05 m, W3: narrow film 1.4 m) and two irrigation water types (M1: magnetized irrigation, M2: unmagnetized irrigation), comprising six experimental treatments, on soil oxygen levels and microbial communities in the cotton rhizosphere. The results demonstrated that the magnetized water irrigation combined with ultra-wide film mulching treatment (W1M1) achieved soil temperature and porosity of 23.49 degrees C and 49.8 %, respectively, both significantly higher than all other treatments. Medium-width film mulching treatments exhibited the highest soil oxygen levels; however, due to the higher porosity and lower soil moisture content under ultra-wide film mulching, the latter demonstrated higher total soil oxygen levels, with W1M1 exceeding W2M1 by 0.07 % and W1M2 surpassing W2M2 by 0.56 % in total soil oxygen content. Furthermore, W1M1 enhances microbial metabolic functions by modulating the relative abundance of microbial communities in cotton rhizosphere soil. The combined relative abundance of Proteobacteria and Actinobacteriota phyla under W1M1 treatment increased by 11.20 % and 14.25 % compared to W2M1 and W3M1, respectively, while the relative abundance of Chloroflexota phylum decreased by 1.07 % and 3.05 % compared to W2M1 and W3M1, respectively. Compared to W2M1 and W3M1 treatments, W1M1 showed increases of 1.79 % and 21.34 % in Carbohydrate metabolism, 5.84 % and 13.04 % in Glycan biosynthesis and metabolism, and 1.98 % and 3.68 % in Membrane transport, respectively. In 2023 and 2024, the W1M1 treatment achieved the highest cotton root dry matter mass, seed cotton yield, and irrigation water use efficiency, recording 38.9 g plant-1 and 40.9 g plant-1 , 6328 kg ha-1and 7545 kg ha-1 , and 1.7 kg cm-3 and 1.8 kg cm-3 , respectively. These findings demonstrate that the W1M1 synergistic technique effectively optimizes soil structure, enhances soil oxygen content, and stimulates microbial metabolic activity, consequently improving cotton yield and water use efficiency, thus providing a promising approach for the widespread implementation of ultra-wide film mulching cultivation technology for cotton production in Xinjiang.