The synthesis of the super-heavy nuclei and the study of their properties attract more and more attentions in recent years. The He-jet+MG wheel technique with which ^259Db and ^265Bh were synthesized at IMP has reached its limits due to the short life-time and rare amount of the products. In order to identify the nuclei with higher Z, a device for separating the interested nuclei from the heavy background is definitely needed.