Electromigration　is　one　of　the　most　stubborn　and　serious　reliability　failure　mechanisms　in　interconnection　wires.　Specifically,　there　is　a　high　risk　of　electromigration　in　the　special　metal　interconnection　electrode　structure　of　high-voltage　light-emitting　diodes　(HV-LEDs).　Nevertheless,　a　systematic　investigation　on　this　issue　is　lacking　in　literature.　Here,　simulations　and　experiments　were　conducted　to　systematically　investigate　the　metallization　reliability　of　gallium　nitride　based　HV-LEDs　(9　V,　100　mA)　which　were　designed　and　fabricated　in　this　study.　The　finite　element　model　of　the　devices　was　established　by　the　ANSYS　software.　Numerical　solutions　of　the　interconnected　electrodes　were　obtained　by　multiphysics　field　coupling　electric-thermal-structure　simulation.　It　was　found　that　the　temperature,　temperature　gradient,　current　density,　and　stress　all　reached　maximum　at　the　n-type　metal　of　the　interconnected　electrode,　which　provided　the　theoretical　support　for　the　experiment.　Then,　the　accelerated　aging　experiment　was　conducted　under　high　temperature　(85　degrees　C)　and　high　current　injection　(100　mA,　130　mA,　150　mA,　170　mA).　It　was　found　that　whiskers　started　to　appear　from　the　sidewalls　of　the　Cr/Al/Cr/Pt/Au　n-type　electrode　after　30　hours　of　burn-in　test.　The　electromigration　was　more　likely　to　occur　at　the　n-type　electrode,　which　was　consistent　with　the　results　of　the　simulation.　Finally,　the　causes　of　the　HV-LED　metallization　failure　were　analyzed.　It　was　determined　that　high　current　density　and　high　temperature　were　the　main　reasons　for　the　electromigration　of　the　interconnected　electrodes　in　HV-LEDs.　This　work　fills　the　knowledge　gap　of　metallization　reliability　study　of　GaN　HV-LEDs　and　is　of　value　to　the　design,　fabrication　and　application　of　the　devices.