Preheating and grinding method was examined as a way for recovery of high quality recycled aggregates from waste concrete. As results, as the preheating temperature increased, the removal rate of cement mortar from waste concrete increased. And when it was treated over $400^{circ}C$ of preheating temperature, the absorption was reduced and cement mortar was effectively separated from waste concrete. It could meet the Korean Standards on aggregates for concrete. It means that recycled aggregates treated by preheating and grinding method can be expected to be used as the utilization which is same to natural aggregates.