GB/T 23595.8-2025 is Part 8 of the series of test standards for rare earth phosphors for LEDs. It specifies the method for determining the high-pressure accelerated aging performance of such phosphors under excitation by ultraviolet to blue light in the wavelength range of 350 nm to 480 nm. This standard is applicable to the performance evaluation of related products in the fields of lighting and display. The standard characterizes the weathering stability of materials by measuring the variation in luminous radiant power and the shift in chromaticity coordinates after accelerated aging for 48 hours under conditions of 0.2 MPa absolute pressure and 100% relative humidity. The test requires the use of instruments such as a high-pressure accelerated aging test chamber, a spectroradiometer, and a chromaticity coordinate tester, providing a unified technical basis for quality control of phosphors and reliability design of LED devices.