A　model　of　internal　heat　source　distribution　is　presented　for　quantum-well　laser.　Three-dimensional　temperature　distribution　of　the　stripe　quantum-well　laser　is　simulated　by　using　the　finite　element　method,　and　the　influence　of　solder　voids　between　chip　and　heat　sink　on　the　steady-state　temperature　distribution　is　discussed.　It　is　found　that　the　chip　s　internal　temperature　distribution　is　influenced　by　the　position　and　size　of　solder　voids.　The　localized　hot　spot　may　result　from　the　nether　solder　voids,　and　the　strong　localized　temperature　rises　and　the　hot　spot　expands　with　the　expanding　of　the　void　s　dimension.　Simulated　result　shows　further　that　the　strongest　temperature　rise　is　caused　by　solder　voids　under　the　center　of　the　electrode　stripe,　and　moreover,　the　highest　temperature　lies　at　the　front　facet.　So　catastrophic　optical　damage　(COD)　will　be　found　at　the　front　facet　most　possibly,　which　is　in　agreement　with　the　test.