A orthoconcrete with high coarse aggregate volume fraction and good aggregate interlock was prepared by Mini-Mason method. The results show that by improving the fluidity of the filling mortar， the volume fraction of coarse aggregate in concrete can be effectively increased to 52%， and the mechanical properties， volume stability， mass transfer performance and interfacial transition zone structure of concrete can be significantly improved， and the bonding state between slurry and coarse aggregate can be optimized， and the use amount of cementing material can be greatly reduced. The experiment proves the feasibility of the Mini-Mason process and provides a new technical advantage for 3D printing orthoconcrete.