Abstract: With the practice of island and reef reclamation projects in the Nansha waters, the research on the physical and mechanical properties of reef limestone has gradually become a research focus in the field of engineering geology. A reef limestone core was obtained from a borehole with a depth of 300 meters on an island and reef in Nansha, and passed the vertical and horizontal wave tests, uniaxial and triaxial compression tests, and reef limestone rheological tests. The following conclusions are obtained:the relationship between the shear wave velocity and the longitudinal wave velocity of the deep reef limestone rock sample is V_s=0.4447V_p+409.94; the reef limestone still has a large bearing capacity after being destroyed, and the reef limestone fractures in a broken strip shape, Breaks along the growth weak surface, the strength of the reef limestone is also very random due to the strength randomness of the cave and the weak surface; the stress threshold for the accelerated creep of the reef limestone is about 5-6 MPa, when the loading level reaches 5-6 MPa the process of accelerated creep occur. The test conclusions provide a basis for the construction of the South China Sea Reef Project, and also provide reference materials for the in-depth study of the engineering geomechanical properties of coral reefs.