Hollow welding ball is a hollow ball made of two hemispheres welded, can be used according to the force size without gallium and gallium two types, in China, welding hollow ball nodes can be used for single layer or multiple layer space grid structure of node system, the system is to weld steel pipe directly with a pre-made hollow ball, suitable for connecting steel pipe rods. Welding hollow ball node's advantage is simple construction, power clear, connection convenient, and its rigidity is much larger than bolt ball node, so it also has a wider range of use than bolt ball node, but the welding hollow ball node's field welding work is large, at the same time, the ball's diameter is much larger than the tube diameter, which becomes a disadvantage in the architecture.