Abstract: The biocemented coral sand pile is a new type of pile, which is a pile of coral sand solidified by biocemention reaction. The effects of relative compactness of coral sand foundation on the bearing capacity settlement, axial force and shaft friction, of single pile are studied by the pile load model tests in the coral sand foundation under different relative compactnesses. The test results show that the biocemented coral sand pile has good strength, and the unconfined compression strength of the pile can reach 12 MPa. When the relative compactness of sand between piles increases, the bearing capacity of single pile will be improved and the settlement will be reduced. The axial force of the biocemented coral sand pile decreases with the increase of the relative compactness and the depth of the coral sand foundation. The shaft friction increases with the increase of the relative compactness, while it increases quickly and then decreases slowly with the increase of the depth. The ratio of the pile end reaction to the total load increases with the increase of the relative compactness of the coral sand between the piles. The findings provide the basis for the engineering application of the biocemented coral sand piles.