IGBTs　have　the　advantages　of　BJTs　and　MOSFETs,　they　are　widely　used　in　household　appliances　and　industrial　production.　But　thermal　problem　has　affected　the　development　of　IGBT,　so　its　accurate　measurement　of　thermal　resistance　and　temperature　rise　is　very　important.　In　this　paper,　we　propose　a　new　test　system　for　thermal　resistance　of　IGBT,　in　this　test　system,　we　use　digital　approach,　choose　the　voltage　between　collector　and　emitter　with　constant　current　and　gate-collector　short　as　heat-sensitive　parameter,　the　results　show　that　this　system　has　the　advantages　of　accuracy　and　good　measurement　reproducibility,　and　it　has　better　feasibility.