Background:　In　order　to　study　the　effect　of　bifurcation　vessels　parameters　on　the　temperature　field　and　coagulation　zone　of　microwave　ablation　on　lung　tissue.　Methods:　The　finite　element　method　was　used　to　establish　the　simulation　model.　The　angle　of　bifurcation　vessel　model　was　60　degrees.　The　position　of　the　antenna　and　the　main　blood　vessel　are　parallel,　and　the　distance　between　them　was　5,　10　and　15　mm,　respectively.　Temperature　field　distribution　was　obtained　at　2450　MHz,　50　W　and　300　s.　The　blood　flow　velocity　was　set　to　0.1　and　0.2　m/s.　Results:　The　results　showed　when　the　antenna　was　5　mm　away　from　the　bifurcation　vessel　and　the　velocity　was　0.1　m/s,　the　position　of　x　=　8.4　mm　achieved　the　complete　necrosis　at　220　s,　while　the　fraction　of　necrotic　tissue　at　the　symmetry　point　x　=　1.6　mm　was　0.2　at　300　s.　For　the　distance　was　10　mm　and　the　velocity　was　0.1　m/s,　the　fraction　of　necrotic　tissue　at　x　=　3　mm　that　near　the　bifurcation　vessel　was　0.53　and　was　0.69　at　the　symmetry　point　x　=　17　mm.　When　the　antenna　is　15　mm　away　from　the　vessel,　the　fraction　of　necrotic　tissue　of　symmetrical　points　on　both　sides　of　the　antenna　obtained　after　ablation　were　the　same.　Conclusions:　The　distance　between　the　antenna　and　the　bifurcation　vessel　over　15　mm,　the　blood　flow　has　no　effect　on　the　coagulation　zone.　Besides,　the　distance　between　bifurcation　vessel　and　antenna　possesses　a　greater　influence　on　the　temperature　distribution　and　coagulation　zone　than　the　blood　flow　velocity.