A kind of orthoconcrete with high volume ratio of coarse aggregate and good interlocking was prepared by Mini-Mason method.The test shows that by improving the fluidity of filling mortar, the volume rate of coarse aggregate in concrete can be effectively increased to 53%, and the mechanical properties, volume stability, mass transfer and structure of interfacial transition zone of concrete can be significantly improved. The bonding state between slurry and aggregate can be optimized, and the amount of cementing material can be greatly reduced.It proves the feasibility and technical advantage of 3D printing positive concrete.