UGR is short for unified glare rating, it measures psychological parameters of subjective discomfort to eyes caused by light fromlighting devices in indoors visual environment, its values can be calculated by thee regulation condition with CIE unified glare value formula. Ugr environmental requirements of lighting products ugr is divided into seven levels, namely 28.25.22.19.16.13.10. 28 nearly unbearable glare value 25 discomfort value 22 nearly discomfor value 19 the boundary between comfort and discomfort 16 nearly acceptable glare value 13 nearky glare value 10 no glare value The illuminance standard of GB50043-2004 mostly is UGR25, UGR22 and UGR19.