The invention relates to a triangular support operating platform device for an outer wall of a racing track. The device comprises transverse fixing rods, telescopic rods, inner wall vertical rods, outer wall vertical rods, vertical protective rods and opposite-pull screws. The transverse fixing rods are provided with bolt holes at intervals and arranged on the side wall of a U-shaped groove, wherein the inner wall vertical rods and the outer wall vertical rods are arranged on the lower parts of one ends of the transverse fixing rods correspondingly and positioned on the two sides of the side wall of the U-shaped groove; the inner wall vertical rods and the outer wall vertical rods are connected through the opposite-pull screws; the other ends of the transverse fixing rods are connected with one ends of the telescopic rods; the vertical protective rods are arranged on the upper parts of the other ends of the telescopic rods; the telescopic rods are provided with bolt holes at intervals;and the vertical protective rods are provided with nuts. The device conforms to the concept of sustainable development, operability is high at a narrow high wall, and the problem that a protective shed is not suitable for being erected at an overhead position during racing track construction is solved.