Hyperspectral imaging represents an electromagnetic spectrum for each pixel in the image of a structural surface. The characteristic wavelength of the spectrum at reflectance valleys or absorption peaks can be used as a spectral feature for certain chemical detection. In this study, spectral reflectance characteristics of mortar samples are extracted to assess the reduction of moisture on the surface of mortar samples during the cement hydration process. The test results indicate that the reflectance increases and the absorbance decreases because water is reacted and less light will be absorbed during the hydration process. The average absorbance between 1923 nm and 1983 nm in wavelength gradually decreases with the mortar curing time. This feature parameter can be used to evaluate the mortar hydration process.