A flexible microwave ablation antenna and a microwave ablation needle including the same are provided. The flexible microwave ablation antenna including: a radiator for transmitting microwave for ablation; a coaxial cable for propagating the microwave for ablation generated by a microwave generator to the radiator; wherein the flexible microwave ablation antenna is bendable. Preferably, an annular composite structure is disposed around a periphery of the coaxial cable so as to suppress the electromagnetic wave from propagating along the coaxial cable in a reverse direction. The annular composite structure includes an annular non-metallic layer and an annular metallic layer surrounding the annular non-metallic layer. The annular metallic layer is electrically insulated from the coaxial cable. The ablation needle of the present disclosure may have a good flexibility and may deeply go into the lungs through the respiratory tract for ablation, which avoids perforation in the lungs, thereby reducing a risk of postoperative complications such as pneumothorax and pneumonia.