OBJECTIVE The objective of this study was to provide specific data and make recommendation for radiation protection for clinical application,neutron cumulative dose and existing time in the treatment room around an accelerator operating at 10 MV both with the condition of conventional dose rate (with the flattening filter,FF mode) and ultra-high dose rate (with the flattening filter free,FFF) were measured and analyzed. METHODS In the accelerator treatment room,the data was collected in four representative sites:therapists operating location,the distal end of the couch in the patient plane,maze proximal and protective door. The field size were 5 cm×5 cm,10 cm×10 cm and 30 cm×30 cm respectively,output dose were 500 MU,1 000 MU and 2 000 MU respectively,the solid water phantom simulating the patient's body was put on the isocentre,dose rate of FF mode was 10 MV X-ray 600 MU/min and dose rate of FFF was 2 400 MU/min. In the same condition the data was collected outside the selected measuring three positions:protective door,operating room and center of main protective wall position. RESULTS The neutron cumulative dose was negatively correlated with field size. The closer to the target,the larger the neutron cumulative dose was. The neutron cumulative dose was the largest in the distal end of the couch. The neutron cumulative dose of FF mode was almost three times as much as that of FFF mode. Neutron existing time was positive correlated with output dose. FF mode took slightly longer than the FFF mode. No neutron dose was read outside the accelerator room. CONCLUSIONS Operating the accelerator of FFF mode will benefit both patients and radiation therapists by reducing the neutron cumulative dose and existing time. Existing anti-neutron accelerator room design is equally applicable to ultra-high-dose rate (FFF) mode accelerator. © 2017, Editorial Board of Chinese Journal of Cancer Prevention and Treatment. All right reserved.