Desert sand (DS), utilized as a substitute for traditional river sand in the production of desert sand concrete (DSC), offers significant environmental benefits, cost savings, and enhanced energy efficiency. Furthermore, carbonation is a common durability issue faced in concrete. Therefore, this study aimed to investigate the carbonation resistance of DSC, the mechanisms underlying microstructural degradation, and the effects of carbonation on its stress-strain curve. Accelerated carbonation tests were performed on concrete samples with varying DS replacement ratios (0 %, 20 %, 40 %, 60 %, 80 %, and 100 %) over carbonation periods of 0, 3, 7, 14, and 28 days. Scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD) microtests, and uniaxial compression tests were conducted, following the carbonation process. The results indicated that: (1) The carbonation depth of concrete with 40 % and 60 % replacement ratios of DS decreased by 25.49 % and 17.65 % respectively, compared to ordinary concrete (OC). (2) A dense concrete with low porosity microstructure was formed at DS replacement ratios of 40 % and 60 %, which retarded COQ diffusion and enhanced carbonation resistance. (3) The SiOQ and AlQO3 in DS influenced the content of the hydration products in cement. (4) As carbonation time increased, the stress-strain curve of DSC gradually converged, with the peak point rising and shifting to the left, indicating a reduction in the material's ductility and plastic deformation capacity. The degradation trend of DSC with 40 % and 60 % DS replacement ratios was mitigated compared to OC. Furthermore, a DSC constitutive model that accounts for both the DS replacement ratio and carbonation time is proposed based on the experimental results. Overall, this study provides a theoretical foundation for the further promotion of DSC.