Abstract: The special engineering mechanical characteristics of coral sand have been widely studied, but the coral sand in special areas is not isolated and often contains siliceous impurities to form coral sand mixture. The influence mechanism of the siliceous impurities on the mechanical deformation characteristics and particle breakage of the coral sand is still unclear. By using the standard quartz sand as the siliceous impurity, the confined high-pressure compression tests under different initial relative compactnesses and sand mass proportions are carried out to study its compression characteristics and particle crushing rules. The experimental results show that with the increasing proportion of quartz sand mass, the compressive deformation of the coral sand-quartz sand mixture decreases. However, the quartz sand has no obvious influences on the trend of its compression curve. The relative compactness, vertical pressure and sand mass proportion all have important effects on the particle breakage of the coral sand-quartz sand mixture. Compared with that at high compactness, the particle breakage effect of the mixture at low compactness is more significant in the process of compression. With the increase of the vertical pressure, the particle breakage effect of the mixture increases gradually. The increasing proportion of quartz sand mass reduces the occurrence of the particle breakage to a certain extent, which is closely related to the high particle strength of the quartz sand. The research results can provide some references for further understanding the influences of siliceous impurities on the compressive deformation and particle breakage of the coral sand.