An anti-floating structure of a cast-in-situ pile reinforced cage comprises a cast-in-site platform, a guide pipe, a reinforced cage, and an anti-floating device. The cast-in-site platform is connected to the guide pipe, and the guide pipe penetrates into the reinforced cage. The anti-floating device comprises an upper hoop, a lower hoop, diagonal support rods, lateral support rods and clamping grooves, the upper hoop is connected to the clamping grooves by the diagonal support rods, and meanwhile, the lower hoop is connected to the clamping grooves by the lateral support rods. Triangle structures are formed among the upper hoop, the lower hoop, and the clamping grooves. The upper hoop and the lower hoop are respectively installed on the guide pipe, and the clamping grooves sleeve the topsof main ribs of the reinforcing cage. The anti-floating structure is suitable for the pile foundation construction of different hole depths, and has strong applicability. Meanwhile, the problems thatthe requirements on the docking precision of the anti-floating device and the reinforced cage are high, and the anti-floating effect is affected since long vertical poles are easy to deform are solved, and the anti-floating structure can be repeatedly assembled and disassembled for use, and is low in cost and high in recycling rate.