A high power magnetron is disclosed. The magnetron includes an anode. The anode has a cylinder positioned around a cathode, a plurality of vanes radially fixed to an inner wall of the cylinder, and straps mounted through the vanes. The inside diameter of the cylinder is 40-43 mm and the thickness of the cylinder is 2.8 mm or less. The magnetron is capable of not only reducing the thickness of its cylinder but also improving the thermal performance of the cylinder, thereby improving thermal stability of the cylinder, lengthening the life span of the cylinder and reducing the fabrication costs of the cylinder.