Because the net primary productivity is low and disturbance effect are strong, desert ecosystems have been proposed conventionally as a carbon source. However, studies worldwide in recent years have reported that desert soils can absorb atmospheric CO₂, and the absorbed carbon may be conserved in soils or aquifers. As the carbon uptake is counterintuitive and the mechanisms of this process are elusive, the authenticity of this process is still grossly controversial. In this paper, we deeply discussed the authenticity of the anomalous carbon absorption and its possible driving mechanisms, and conclude that the counterintuitive process is authentic. The thermal mechanism, surficial turbulence and pressure gradients variations driving CO₂ migration may be the important driving mechanisms. However, heretofore, no direct evidence can be provided for the speculation that the carbon absorbed by desert soils can commonly and rapidly transport into underground water or mineralize and sequestrate in soil. As a result, the role of carbon sink of desert soils remains veiled. It was suggested that future researches should focus on the transportation and emphatically focus on the gaseous transformation and mineralization of the liquid phase carbon.