The utility model belongs to the technical filed of steel bricks for tunnel kiln cars, and concretely relates to a tunnel kiln car steel brick damage supplement structure which solves a series of problems brought about by partial damages of tunnel kiln car steel bricks. The structure comprises a steel bar support, two ends of the steel bar support penetrate into steel bricks adjacent to a damaged steel brick, a template is arranged at a position corresponding to the outer surface of the damaged steel brick and is welded with the steel bar support, and the internal space of the template is poured with castable. The tunnel kiln car steel brick damage supplement structure has the characteristics of being simple in operation, low in manufacturing cost, timely in replacement, and strong in durability and practicability; and service lift of the structure can be more than 10 times as long as conventional steel bricks, thereby greatly reducing maintenance and replacement times for steel brick damages and dropping, prolonging service life of a bottom bearing of a kiln car, enabling temperature inside the kiln to be stable for a long time, ensuring normal production of the tunnel kiln, and raising production quality.