A　thermal　analysis　of　AlGaN/GaN　high　electron　mobility　transistors　(HEMTs)　with　Graphene　is　investigated　using　Silvaco　and　Finite　Element　Method.　Two　thermal　management　solutions　are　adopted;　first　of　all,　graphene　is　used　as　dissipation　material　between　SiC　substrate　and　GaN　buffer　layer　to　reduce　thermal　boundary　resistance　of　the　device.　At　the　same　time,　graphene　is　also　used　as　a　thermal　spread　material　on　the　top　of　the　source　contacts　to　reduce　thermal　resistance　of　the　device.　The　thermal　analysis　results　show　that　the　temperature　rise　of　device　adopting　graphene　decreases　by　46.5%　in　transistors　operating　at　13.86　W/mm.　Meanwhile,　the　thermal　resistance　of　GaN　HEMTs　with　graphene　is　6.8　K/W,　which　is　much　lower　than　the　device　without　graphene,　which　is　18.5　K/W.　The　thermal　management　solutions　are　useful　for　integration　of　large-scale　graphene　into　practical　devices　for　effective　heat　spreading　in　AlGaN/GaN　HEMT.