AZ61A magnesium alloy tube with large diameter and thin wall was fabricated by centrifugal casting technique. The microstructures and tensile properties of the tube were studied and it was compared with the conventional sand casting. The results show that the grains of the tube by centrifugal casting are significantly refined. The eutectic transformation L→ α-Mg+β-Mg17Al12 are suppressed to a great extent under the balanced solidification condition. As a consequence, the alloying elements Al and Zn show much higher solid solubility and the microstructure of the tube dominantly consists of supersaturated primary α-Mg solid solution. The tensile properties of the centrifugal casting tube are remarkably increased. In addition, the fracture surfaces exhibit amounts of dimples, indicating quasi-cleavage ductile fracture characteristics, and the ductility is improved obviously