Abstract: Materials as bentonite, straw, artemisia gum are often used to mitigate obstacles such as water and nutrient leaching in sandy soils. Preparing and exploring composite functional materials based on bentonite, straw and Artemisia gum for soil improvement and fertilization can provide a new approach for the comprehensive improvement of sandy soil, this study conducted a 90 d field control experiment in farmland within the Mu Su sandy land. The experiment investigated the impact of three material ratios (C1: bentonite∶ straw∶ artemisia gum = 0.5∶1∶0.4; C2: bentonite∶ straw∶ artemisia gum = 1∶1∶0.4; C3: bentonite∶ straw∶ artemisia gum = 2∶1∶0.4) on soil water retention, nutrient preservation, and bacterial community diversity in sandy soil. The results of the study were as follows: 1) The application of composite materials has demonstrated significant improvements in potato tuber quality and soil water retention capacity in sandy soil. Among them, the C1 treatment group demonstrated the most pronounced improvement in yield enhancement and water conservation compared to the control (CK), with soil saturated hydraulic conductivity reduced by 88.24%, and soil moisture content increased by 1.64 fold; 2) The combined application of all three composite materials significantly increased the soil available phosphorus (AP) and available potassium (AK) contents, with increments ranging from 14.3% to 74.22% and 29.50% to 104.64%, respectively; 3)The application of three composites consistently enhanced the overall stability of bacterial communities in sandy farmland soil. Specifically, it elevated the abundance of eutrophic bacterial phyla such as Proteobacteria, Firmicutes and Bacteroidetes, while significantly promoting functional taxa including Bacillus and Microvirga, which are known for phosphate-solubilizing, potassium-mobilizing, and plant growth-promoting activities. From the perspective of comprehensive soil improvement, the C1 formulation demonstrated superior applicability for rehabilitating sandy agricultural soils. These findings provide both a theoretical foundation and technical support for the integrated restoration of degraded and nutrient-poor sandy soils in potato cultivation systems.