This work presents the design and testing of a 3D positioning system for precise location of microwave ablation (MWA) antennas. MWA increases tumor temperature between 60 ℃ and |100 ℃ through electromagnetic radiation, inducing coagulative necrosis while minimizing damage to healthy tissue. A major challenge in this technique is maintaining accurate and stable antenna placement, especially when multiple antennas or deeper insertions are required. To address this, a 3D positioning system was developed using 3D printed, non-metallic, and heat-resistant materials to prevent electromagnetic interference. The scanner allows movements along the X, Y, and Z axes and adjustment of insertion angles (θ, β, and φ), making it adaptable to different anatomical regions and antenna configurations. Experimental tests were carried out using Double-slot antennas on multilayer phantoms, applying 10 W. The system ensured stable antenna positioning, minimal reflected power, and accurate thermal imaging. This 3D scanner can already be used to evaluate the performance of MWA systems in multi-layer phantom or ex-vivo porcine tissue.