Changes in spectral properties of output light are analyzed from the angle of integrating sphere non-neutrality.Based on integrating-sphere theory,the relationship between non-neutrality of integrating-sphere spectral transmittance and that of spectral reflectance of inner coating is derived.It shows that non-neutrality of integrating spheres is usually greater than that of inner coatings,and integrating sphere non-neutrality increases with the rise of coating reflectance when coating non-neutrality remains unchanged.Then spectral distribution,chromaticity coordinates and color temperature of output light are measured under illumination of light source A and a Xenon lamp respectively.The measurement results indicate that effects of non-neutrality of barium sulfate and polytetrafluoroethylene integrating spheres on output spectrum are both the increase of chromaticity coordinates and decrease of color temperature.For the polytetrafluoroethylene integrating sphere,color temperature of output spectrum is reduced for about 20 K and 70 K respectively when incident light source is light source A and a Xenon lamp.While for the barium sulfate integrating sphere,color temperature is reduced for about 300 K and 1 000 K respectively,which implies more remarkable influence on output spectrum.