In order to improve the purification ability to non-point pollution of the revetment material, the porous eco-block with high permeable rate was prepared by the aggregate cross-linking method to study the relationship of particle size and permeable rate. The surface load of denitrifying bacteria was carried out on the eco-blocks with different permeable rate by the method of biofilm formation in flowing water. On this basis, the coupling effect of water permeation rate and surface area of the porous eco-block with different aggregate size on the removal rate of nitric nitrogen in water was studied. The results show that, in the same porosity, the permeable rate of the porous block decreases when its specific surface area increases, while increasing when its aggregate size expands. The removal rate of nitric nitrogen in water decreases after increasing when the permeable rate of the porous eco-block increases, the removal rate of nitric nitrogen by the porous block can be up to 90. 3% when the aggregate size of the porous eco-block is 7~11 mm and its permeable rate is 6. 6 mL/(s·cm²).