The　relaxation　of　the　misfit　strain　by　the　formation　of　misfit　dislocations　in　InxGa1-xN/GaN　multiple　quantum　wells　grown　by　metal-organic　chemical-vapor　deposition　was　investigated　by　the　cross-sectional　transmission　electron　microscopy,　double　crystal　x-ray　diffraction,　and　temperature-dependent　photoluminescence.　It　is　found　that　the　misfit　dislocations　generated　from　strain　relaxation　are　all　pure-edge　threading　dislocations　with　burgers　vectors　of　b=1/3＜11　(2)　over　bar0＞.　The　misfit　dislocations　arise　from　the　strain　relaxation　due　to　the　thickness　of　strained　layer　greater　than　the　critical　thickness.　The　relaxation　of　strained　layer　was　mainly　achieved　by　the　formation　of　dislocations　and　localization　of　In,　while　the　dislocations　changed　their　slip　planes　from　{0001}　to　{10　(1)　over　bar0}.　With　the　increasing　temperature,　the　efficiency　of　photoluminescence　decrease　sharply.　It　indicates　that　the　relaxation　of　the　misfit　strain　has　a　strong　effect　on　optical　efficiency　of　film.　(C)　2004　American　Institute　of　Physics.