A　three-dimensional　electrical-thermal　coupling　model　based　on　the　finite　element　method　is　applied　to　study　thermal　properties　of　implant-defined　vertical　cavity　surface　emitting　laser　(VCSEL)　arrays.　Several　parameters　including　inter-element　spacing,　scales,　injected　current　density　and　substrate　temperature　are　considered.　The　actual　temperatures　obtained　through　experiment　are　in　excellent　agreement　with　the　calculated　results,　which　proves　the　accuracy　of　the　model.　Due　to　the　serious　thermal　problem,　it　is　essential　to　design　arrays　of　low　self-heating.　The　analysis　can　provide　a　foundation　for　designing　VCSEL　arrays　in　the　future.