Specific　Absorption　Rate　(SAR)　represents　the　electromagnetic　radiation　sorption　ability　of　the　biological　organisms.　It　is　a　hotspot　issue　in　thermal　ablation.　Different　antenna　structure　can　get　the　different　SAR　in　clinical　treatment.　This　study　use　simulation　software　HFSS　which　based　on　finite　element　method　simulate　the　SAR　of　two　microwave　antenna　(ETW　antenna　and　Cap-Choke　microwave　antenna).　Obtain　the　curves　of　SAR　distribution,　predict　the　temperature　field　more　accuracy　and　provide　method　to　design　microwave　antenna.　The　ratio　of　the　long　axis　and　short　axis　of　Cap-Choke　antenna　is　about　3:2,　while　the　ratio　of　ETW　antenna　is　4.7:1.7.　So　Cap-Choke　antenna　is　suitable　for　the　ablation　of　tumor,　while　ETW　antenna　can　meet　to　the　requirement　of　linear　ablation　area　in　atrial　fibrillation　ablation　therapy.　©　(2014)　Trans　Tech　Publications,　Switzerland.