Seasonal variation in spectral characteristics of Moss Soil Crust (MSC) under different moisture conditions highly affects the application of remote sensing on determining the fraction cover and productivity of MSC. However, relatively little research has focused on it. This study thus aimed to fill the gap by analyzing in situ measurements of spectral reflectance of dry and wet MSC as well as bare soil. Results show that the spectral response curve of dry MSC is similar to that of bare soil, while the wet MSC alive demonstrates a similar spectral characteristic with higher plants. Similar to higher plants, the spectral reflectance of wet MSC varies seasonally indicated by a large difference in July and October, and so does that of dry MSC. In addition, the spectral reflectance of MSC changes as soil moisture changes. Hence, the applicability of remote sensing approaches developed only based on the difference of the spectral response curve of MSC from other ground objects under certain condition is much reduced. Besides, the similarity in the spectral reflectance curves of wet MSC and higher plants may result in the misinterpretation of vegetation indices and the overestimation of vegetation productivity in an area covered by abundant mosses. The misinterpretation of vegetation indices could be more severe due to the Maximum Value Composite (MVC) technique used to compose the global vegetation maps in the study of vegetation dynamics.