The variability of reclaimed asphalt mixtures (RAP) is one of the important factors to affect the mix design and pavement performances of the reclaimed asphalt mixtures. Therefore, in the engineering practice, it is urgently to pretreat RAP material and separate the aged asphalt and aggregates in order to reduce the variability. Based on this, a new separation method of RAP oilstone named the refined oilstone separation technology is introduced including its technological process. The separation effect is experimentally evaluated. The refined separated RAP material is used to prepare the reclaimed mixture and to apply in the practical projects. The result shows that the RAP material after refined separated and treated is even and stable, and the variability meets the requirements. The performance indexes of used aggregates are basically same as the new aggregates. Various pavement performances of reclaimed asphalt mixture all satisfy the requirement. The construction quality of high-class pavement is controllable and reclaiming effect is good.