The utility model relates to a tubular joint, in particular to a space structural butterfly-shaped cast steel tubular joint, which is used for a large-span space pipe truss in the field of building steel structures. The cast steel tubular joint comprises a main tube and branch tubes, two pairs of branch tubes are inserted on the main tube and extend obliquely outwards, the main tube and the two pairs of branch tubes form the shape of a butterfly, each branch tube comprises a connecting plate, a truncated cone and a web member, the connecting plate is fixed with the main tube, the truncated cone is arranged between the web member and the connecting plate, and chord member connecting sites are arranged on two side walls of the main tube. The cast steel tubular joint is simple in structure, reasonable in stress, lower in construction difficulty and higher in safety.