Customs inspections are very important for the protection of our national property, and human blood is an important part of the national property. Therefore, discrimination between human and nonhuman blood is very important. In this paper, visible diffuse reflectance spectra and partial least squares discriminant analysis (PLS-DA) were used to discriminate human and nonhuman blood. A blind test and an external validation test were used to assess the PLS-DA model. The model demonstrated 100% accuracy in its differentiation between the human and nonhuman blood. The results further demonstrate a great potential of visible diffuse reflectance spectroscopy for blood inspection.