Abstract: Zhang-Jing-Gao Yangtze River south channel bridge with span of 2300 meter is the longest suspension bridge in the world. South main tower of the Bridge is 350 meters high. In the base segment, 120mm super thick bearing plate is used for anchoring. Base segment is a combined structure of steel box, steel pipe and concrete with characteristics of bearing high force, complicated structure, super thick plates and huge quantity of welding. Many difficulties like weld deformation control, dimension control and tower axis control happened during fabrication.Studies are conducted on fabrication procedure, difficulties analysis and control points so that base segments are fabricated successfully.