The utility model relates to the underground diaphragm wall construction technology. The utility model provides an anti-streaming device for an underground diaphragm wall joint. The device comprises areinforcement cage, an I-shaped steel joint and a galvanized steel sheet, the galvanized steel sheet edge is welded at the wing plate end of the I-shaped steel joint; the galvanized steel sheet becomes an additional wing plate of the I-shaped steel joint; the utility model relates to a steel reinforcement cage. The device further comprises a joint pipe and a sand bag section, the section size ofthe joint pipe is slightly smaller than the in-groove size of the I-shaped steel joint; the sand bag section is formed by stacking a plurality of sand bags; the sand bag section and the joint pipe endare butted to form a temporary plugging column which is arranged in an outer groove of the I-shaped steel joint; underground diaphragm wall construction, the concrete extrudes the edge part of the galvanized steel sheet outwards to abut against the groove wall and prevent the concrete from flowing around the outer side of the I-shaped steel joint; a small amount of concrete flowing around the I-shaped steel joint is filled and blocked by the temporary blocking column, and the problem that the concrete flows around the I-shaped steel joint during first-stage groove section construction is effectively solved, so that the concrete punching difficulty during second-stage groove section joint construction is reduced, the construction efficiency and quality are improved, and the device has thecharacteristics of simple structure, convenience in operation and practicability.