Abstract: Superconducting fragment separator HFRS is the significant facility to study the radioactive physics in High Intensity heavy-ion Accelerator Facility (HIAF). HFRS is an in-flight fragment separator, which has many unique features, such as large magnetic rigidity, large acceptance, big magnet aperture, high momentum resolving power and so on. HFRS uses the B-E-B method to separate the exotic nuclei produced by projectile fragmentation or fission within several hundred nanoseconds, which are used to investigate the high precision in-ring experiments or out-ring experiments. This presentation mainly introduces the separation performance of HFRS. It uses MOCADI program to simulate the purification of fragments in projectile fragmentation and fission products with one degrader stage or two degrader stages. The simulation results show that HFRS has good achromatic and focusing properties, and it can efficiently isolate and purify light nuclides via fragmentation with one degrader stage and it has a certain separation effect of heavier nuclides with two degrader stages. The momentum spread of fission is much higher than fragmentation, so the fission products separation effect of HFRS with two degrader stages is not as good as the fragment purification effect with single degrader stage.