The system of Circular orbit of 65 meters wavelength telescope in Shanghai is under construction now, which has the biggest caliber and the wholely moveable telescope antenna with high accuracy in line with the international advanced level. The system of antenna weighs 2468 tons. The 65 meters antenna orbit is the foundation for the azimuth rotational motion of the whole antenna system. The orbit is welded after milter joint by 30 sections, whoes diameter is 42 meters. Surface accuracy , strength and greater stability must be guaranteed for the orbit construction. The institute 54 of China Electronics Technology Group Corporation is in charge of the exploration and development of the antenna. Our company is responsible for the welding of this project. Our company fufilled the job of welding marvellously by virtue of the special and advanced welding technology and experience.