Reliability　is　important　in　evaluating　semiconductor　device　quality,　although　reliability　measurement　and　analysis　procedures　are　complicated.　A　new　type　of　light-emitting　diode　(LED),　GaN　high-voltage　(HV)　LEDs,　is　superior　to　traditional　low-voltage　LEDs　owing　to　fundamentally　higher　lighting　efficiency　and　a　simpler　driving　circuit.　Recently,　HV-LEDs　have　received　much　interest,　and　related　commercial　devices　have　been　developed.　However,　reports　on　HV-LED　reliability　are　very　rare.　Therefore,　herein,　we　conduct　a　systematic　study　of　the　reliability　of　commercial　HV-LEDs.　In　current　stress-accelerated　lifetime　testing　experiments　on　HV-LEDs　(50　V)　for　2,000　h,　the　luminous　flux　of　white　LEDs　was　reduced　by　2.5%-9%　and　the　luminous　efficacy　by　2.7%-11.3%　after　aging.　The　forward　voltage　was　increased,　the　blue-and　yellow-light　irradiations　of　white-light　HV-LEDs　were　reduced,　and　the　excitation　efficiency　of　fluorescence　powders　was　decreased.　Detailed　analysis　is　carried　out　on　a　sample　exhibiting　catastrophic　failure.　The　abrupt　drop　in　luminous　flux　noted　can　be　attributed　to　cracking　of　the　fluorescent　layer　and　reduction　of　optical　transmittance　in　the　epoxy　resin,　rather　than　deterioration　in　the　chip　itself.　Finally,　an　improved　lifetime-prediction　method　based　on　Bayesian　statistics　is　proposed.　Compared　to　conventional　lifetime-calculation　methods,　this　method　combines　experimental　data,　the　conventional　model,　and　historical　information　rationally.　Therefore,　it　provides　lifetime　prediction　at　a　higher　confidence　level:　the　HV-LED　lifetime　is　estimated　as　18　517　h.　The　results　reported　can　guide　the　design,　manufacturing,　and　packaging　of　HV-LEDs,　while　the　new　lifetime-estimation　method　is　valuable　to　reliability　evaluation　of　power　electronic　devices　in　the　semiconductor　industry.