To solve the problem of the non-spherical ablation zone in microwave ablation, we propose a hollow microwave ablation antenna. Compared with the microwave ablation antenna with coaxial cable as the main body, we use a hollow structure instead of the coaxial cable in the antenna to reduce the external conductor current and achieve a spherical ablation zone. We match between the antenna and the coaxial cable by an L-type matching network. The simulated results show that the roundness of the ablation zone of the hollow antenna is more than 85 % at 20 W and 600 s compared with the coaxial microwave ablation antenna. The hollow antenna operates at 2.45 GHz in the egg white, and the ablation experiment was carried out at the 20 W power for 600 s. The experimental results were in good agreement with the simulated results, which verified the ability of the antenna to generate a spherical ablation zone. The hollow antenna can effectively avoid damaging normal tissue and improve the accuracy and efficiency of microwave ablation.