Abstract: The experiment of post grouting for underwater cast-in-pace bored piles has been constructed based on a large industrial construction project located in the East and West Lake area in Wuhan. Underwater cast-in-pace bored piles is adopted in the foundation design. For different pile diameters, different pile lengths at the same bearing layer of pile tip, the respective experiment of the bearing capacity of single pile is tested by post grouting and non-grouting. By the internal force test of pile body, the distribution law of pile side resistance and pile tip resistance with the increase of the pile top load under different working conditions are revealed, and the pile tip and pile side load sharing ratios are also obtained, which provides reference for the further design and construction of the pile foundation.