Abstract: The evolution characteristics of pore structure during loading have an important influence on the mechanics of coral sand. Using the self-developed high-pressure geotechnical CT-triaxial apparatus, the triaxial consolidated tests on the coral sand with a confining pressure of 100~1600 kPa are carried out under the premise of ensuring the conventional size of samples. The real-time CT scanning of the coral sand samples is carried out during loading. The shape parameters of pores like sphericity and anisotropy are analyzed according to the CT images, and the evolution characteristics of pore structure for the coral sand are analyzed by the digital volume correlation method. The results show that the evolution of pore structure for coral sand samples during the loading process can be roughly divided into three stages under the influences of confining pressure and particle breakage. That is, the loading end (section Ⅰ) is mainly affected by compression, the porosity decreases because of the particle breakage and movement, and the local strain is mainly negative. While in the middle and lower parts of the samples (sections Ⅱ and Ⅲ), the combination of slipping particles and increasing porosity macroscopically shows dilatation at low confining pressure, and the local strain shows positive strain. However, the high confining pressure and particle breakage inhibit dilatation. It is explained that the shear zone of the sand samples often occurs in the middle and lower parts of the samples at low confining pressure. During loading, the pore shape of the samples becomes closer to spherical and isotropic with the increase of confining pressure, and the deformation of the samples increases with the axial strain and gradually decreases under the constraint of high confining pressure. The pore volume and local strain of the samples are gradually stabilized during loading. The research results are of great significance for understanding the engineering mechanical properties of the coral sand.