Object:　Microwave　ablation　has　been　widely　used　in　tumor　treatment,　and　the　antenna　is　a　critical　component　of　microwave　ablation.　We　aimed　to　evaluate　a　single-slot　antenna　to　generate　a　small　volume　ablation　zone　(0.5　similar　to　4cm(3))　in　adrenal　tissue.　Methods:　A　three-dimensional　numerical　model　of　the　adrenal　tissue　was　built　and　solved　by　the　Finite　Element　Method.　In　the　simulation　model,　the　slot　antenna　was　placed　between　the　adrenal　gland　and　fat,　and　the　microwave　ablation　power　and　time　were　adjusted　to　obtain　the　target　ablation　zone.　In　ex　vivo　experiments,　the　length　and　width　of　the　ablation　zone　were　measured,　and　the　significance　of　ablation　parameters　on　it　was　determined　using　a　multi-factorial　analysis　of　variance　method.　The　temperature　versus　time　curves　at　3mm　and　7mm　from　the　antenna　were　plotted　to　validate　the　simulation.　Results:　The　simulation　results　showed　that　the　combination　of　microwave　ablation　parameter　settings　30W/300s,　40W/180s,　and　40W/300s　could　create　ablation　zones　in　the　adrenal　tissue　volumes　of　1.4,1.17　and　3.28cm(3),　respectively,　with　minimal　damage　(less　than　0.18cm3)　to　the　surrounding　fat　tissue.　Both　power　and　heating　time　significantly　affected　the　length　and　width　of　the　ablation　zone.　The　temperature　rise　curves　obtained　in　the　simulation　and　ex　vivo　experiments　were　in　good　agreement.　Conclusion:　This　work　shows　that　utilizing　a　slot　antenna　can　produce　a　small　volume　ablation　zone　in　adrenal　tissue　for　microwave　ablation　of　benign　adrenal　adenomas.