Water permeable brick and preparation method thereof

The invention discloses a water permeable brick and a preparation method thereof. The water permeable brick comprises two parts, namely a surface layer and a base layer, wherein the material of the surface layer is prepared from the following components in percentage by mass: 60-70% of ceramic sand, 15-20% of sand and 15-20% of cement, and in addition to the solid components with the sum of 100% in percentage by mass, water accounting for 50-60% by mass of cement is further added; and the material of the base layer is prepared from the following components in percentage by mass: 45-65% of building silt unburned ceramsite, 10-15% of cement, 5-10% of fly ash, 10-15% of melon seed-shaped drug slices and 10-15% of sand, and in addition to the solid components with the sum of 100% in percentage by mass, the water accounting for 30-40% and a water reducer accounting for 1-1.5% relative to total mass of the cement and the fly ash are further added. The water permeable brick disclosed by the invention is prepared by using the building silt unburned ceramsite to replace natural aggregate or calcined ceramsite, on one hand, the using ways of the building silt unburned ceramsite can be expanded, the utilization rate of solid wastes is improved, and negative effects on an environment are reduced, and on the other hand, the obtained water permeable brick has excellent performance.