In order to change the problems of a large amount of surplus concrete slurry and uneven distribution of aggregate settlement in pavement engineering, the C25 fluid concrete was transformed into orthoconcrete by using the distributing-filling aggregate process. The influence of coarse aggregate distributing-filling ratio on the mechanical properties, drying shrinkage and impermeability of orthoconcrete was studied, and the optimum distributing-filling ratio of coarse aggregate was changed by adjusting the dosage of water reducing agent. The interfacial transition zone and pore structure of orthoconcrete were analyzed. The results show that the aggregate distribution in orthoconcrete can be optimized by the distributing-filling aggregate process. Increasing the distributing-filling ratio can make the distribution of coarse aggregate in orthoconcrete uniform, improve the microstructure of interfacial transition zone, reduce the average pore size and porosity. The optimum distributing-filling ratio of coarse aggregate can be increased by 5 percent point when the original dosage of water reducing agent is increased by 10 percent point. In the range of 0%~25% coarse aggregate distributing-filling ratio, the strength of orthoconcrete increases first and then decreases with the increase of distributing-filling ratio.