Abstract: According to the results of load tests on piles, the influence of pile tip post-grouting on the load bearing behavior of super-long large-diameter bored piles in cohesionless soil is analyzed. The test results show that the grouting cement can reach 16.0 m from the pile tip under the geological and construction conditions. The values of the ultimate bearing capacity, tip resistance and skin friction of the test piles after grouting are 1.59, 3.23 and 1.23 times those of bored piles without grouting. A conclusion is drawn that by using the tip post-grouting technique, it saves investment, improves construction quality and reliability, and brings considerable economic benefits and good socio-environment effects. Therefore it is instructive for the design and construction of similar piles.