The invention relates to an indoor hyperspectral bidirectional reflectance distribution function (BRDF) determining system, which comprises a light source area, a hyperspectral auxiliary brightness gauge adjusting area, a carrier stage area and a base which is horizontally placed; the light source area comprises a light source, a light source space adjusting valve, a light source supporting rod and a semi-arc slide rail, wherein the light source is hinged with the circular center of the semi-arc slide rail which is fixed on the side surface of the base through the light source supporting rod; the hyperspectral auxiliary brightness gauge adjusting area comprises an auxiliary brightness gauge, a space adjusting device, a quarter-arc slide rail and a hollow rotary disc, wherein the carrier stage area is arranged on the center of the base, and the hollow rotary disc is fixed on the center of the base; an optical axis of the light source always points to the center of the hollow rotary disc; and both the light source and the auxiliary brightness gauge are powered on. The indoor hyperspectral BRDF determining system has beneficial effects that: shade can be eliminated, the measuring precision can be improved, and the flexibility of the measuring range can be improved; and the rotation of the carrier stage can introduce the azimuth angle characteristic of the BRDF light source, so the completeness of the BRDF determination can be enhanced.