Concrete is produced using abundant desert sand resources from northwest China to alleviate the conflict between increasing demand for river sand and the scarcity of natural sand. It is also intended to address durability challenges in the saline regions of northwest China. Based on chloride-salt natural immersion tests, six groups of concrete with desert-sand replacement ratios of 0, 20%, 40%, 60%, 80% and 100% were prepared and were immersed for 150 days. During immersion, mass, relative dynamic elastic modulus, compressive strength, and splitting tensile strength were measured. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) were used to characterize the deterioration mechanisms. A damage-degradation model under chloride-salt exposure was then established. Results show that chloride-salt exposure causes slight increases in mass and relative dynamic elastic modulus of the desert-sand concrete. The strength of the concrete is also increased. The effect is greater for mixtures with low desert-sand replacement ratios. SEM and XRD results indicate that NaCl crystals and the salt-invasion product Friedel's salt are deposited in pores and cracks near the interfacial transition zone (ITZ). This deposition is the primary cause of the observed macroscopic performance improvement. Damage is defined using damage mechanics theory. The experimental data are fitted with a quadratic parabolic function. The resulting damage model for chloride-salt exposure shows high R² values. All R² values are greater than 0.96.