The　degradation　of　a　device　can　be　described　by　the　degradation　model　in　the　accelerated　tests.　Because　the　degradation　is　closely　related　to　the　degradation　mechanism,　which　reflects　the　intrinsic　physical　or　chemical　reactions,　the　degradation　model　can　be　established　based　on　the　temperature　effect　on　the　reaction　rate　and　the　change　of　reaction　volume　concentration　in　the　physical/chemical　reactions.　Different　degradation　processes　can　be　studied　using　the　degradation　model,　including　both　the　monotonic　and　nonmonotonic　degradation　processes.　Moreover,　the　accelerated　test　is　carried　out　for　the　GaN　LED,　figuring　out　the　parameters　for　the　degradation　model,　the　ratio　of　different　degradation　processes,　and　the　time　constant.