Abstract: Appropriate amount of desert sand as fine aggregate can effectively improve the compressive strength of concrete, and the incorporation of steel fiber has a significant effect on the tensile properties of concrete. In order to explore the flexural mechanical properties of steel fiber desert sand concrete beams, 11 test beams were designed to study the influence of steel fiber volume content, desert sand replacement rate and reinforcement ratio on flexural beams. The result shows that the flexural bearing capacity of steel fiber desert sand concrete beam is increased by 4%-22% compared with that of ordinary concrete beam, and the number of cracks in the flexural beam decreases with the increase of steel fiber content. Steel fiber reduces the elastic-plastic deformation of concrete surface, and the ‘bridge action’ inhibits the generation of cracks and improves the bearing capacity of the test beam. With the increase of reinforcement ratio, the main crack width decreases, but the ultimate load increases gradually, which indicates that the reinforcement ratio is one of the main factors affecting the bearing capacity of the bending beam. The ‘filling effect’ of desert sand compacts the concrete and makes the overall performance of the component present a good state. The cracking load of the test beam and the corrected theoretical calculation value of ultimate bending moment are in good agreement with the test value, and the error is less than 5%. The preparation of concrete by desert sand instead of engineering sand can give full play to the advantages of local resources, save river sand resources, protect the ecological environment of rivers and lakes, and achieve the goal of green building.