As　is　well　known,　the　base　Ge　composition　can　improve　the　DC　characteristics,　frequency　characteristics　and　noise　characteristics　of　SiGe　HBTs.　However,　the　reports　about　the　effects　of　Ge　profile　on　HBTs　thermal　characteristics　are　rare.　In　this　paper,　by　use　of　SILVACO　simulator,　the　effects　of　different　Ge　gradients　on　thermal　and　electrical　characteristics　of　SiGe　HBT　are　investigated.　It　is　found　that　under　the　same　total　Ge　amount　condition,　as　Ge　gradient　increases,　the　f(T)　of　device　increases　significantly,　the　uniformity　of　temperature　distribution　becomes　better,　the　influences　of　temperature　on　the　beta　and　f(T)　are　weakened,　but　the　gain　beta　becomes　smaller.　For　the　device　with　uniform　Ge　composition,　the　beta　is　high,　but　the　influence　of　temperature　on　the　beta　is　enormous,　the　uniformity　of　temperature　distribution　is　poor.　Based　on　these　results,　in　order　to　make　a　tradeoff　among　thermal,　gain　and　frequency　characteristics,　a　novel　Ge　composition　structure　with　the　combination　of　the　uniform　and　graded　Ge　composition　is　proposed.　The　results　show　that　the　novel　Ge　composition　structure　SiGe　HBT　has　good　performances　lower　peak　temperature,　better　uniform　temperature　profile,　smaller　variabilities　of　beta　and　f(T)　with　temperature,　sufficient　high　beta　and　f(T)　compared　with　the　uniform　Ge　composition　device.　These　new　results　provide　valuable　reference　for　the　device　thermal　design,　and　are　supplemental　to　the　research　and　application　of　SiGe　HBTs.