A chair leg telescopic structure for a child dining chair comprises a seat and a chair leg assembly, the chair leg assembly at least comprises a first chair leg and a second chair leg, the seat is rotationally unfolded or rotationally folded on the first chair leg, and the second chair leg is connected with the lower end of the first chair leg in a sleeving, telescopic and sliding mode; a slidingclamping assembly is arranged between the first chair leg and the second chair leg, the seat drives the sliding clamping assembly to slide between the first chair leg and the second chair leg when being unfolded or folded in a rotating mode, and stretching positioning or contracting storage is achieved between the first chair leg and the second chair leg through sliding of the sliding clamping assembly. Due to the improvement of the structure, the unfolding, using, stretching and retracting storage steps among the seat, the first seat leg and the second seat leg can be simplified, meanwhile, the problem that a child is injured due to the fact that the seat, the first seat leg and the second seat leg cannot be positioned and folded again in the using process is solved, and practicability ishigh.