The measurement principle and method of the bidirectional reflectance distribution function (BRDF) are presented. A setup for measuring BRDF is built. The setup can be used to measure the BRDF in both the visible band and the infrared band. In the visible band, a tungsten halogen lamp is used as a light source and a fiber optical spectrometer is used as an optical receiver. The BRDF is measured at a wavelength interval of 10 nm. In the infrared band, a silicon carbide material is used as an infrared source and a pyroelectric detector is used as an optical receiver. The BRDF of a sample is measured through indirect calibration of a standard plate. The measurement repeatability of BRDF is less than 1.5 percent in the visible band, equal to or less than 2.5 percent in the range from 3 μm to 5 μm and less than or equal to 3.0 percent in the range from 8 μm to 12 μm. The experimental result shows that the BRDF measurement setup is highly effective.