The invention discloses a process for preparing high-performance composite concrete from mineral powder, machine-made sand and waste concrete. The process comprises the following steps of 1, the process of preparing the mineral powder, wherein the mineral powder is dried and pulverized through a vertical mill; 2, preparation of the machine-made sand, wherein incoming main raw materials broken stone or stone chips with the particle size smaller than or equal to 40 mm are placed in a piling shed for natural air drying, then sent to a feeding grade-level funnel, fed through a feeding valve and elevated through a belt conveyor and a belt-bucket elevator to enter a sand-making tower, the broken stone or stone chips pass through a sand-making shaping machine, a powerful air sieve and a graduation adjusting machine from top to bottom, a centralized pulse cloth bag type dust collector is adopted, discharging is conducted, so that a finished product, namely the machine-made sand, is obtained, and remaining aggregate returns to the belt-bucket elevator for re-circulation treatment; 3, the process of preparing regenerated aggregate from the waste concrete, wherein the waste concrete is subjected to artificial sorting, simple crushing, separation, sieving and reinforcing, so that the regenerated aggregate is obtained. The process has the advantages that discharging and piling of waste are reduced, and the treatment site is saved.