[en] The Monte Carlo neutron transport code (MCNPX) is used to carry on the neutronics calculation for CFETR magnet system, and its activation analysis is performed by FISPACT, a European activation calculation code, besides. The calculated results show that the max neutron energy flux is 3.97 × 10¹⁴MeV·m^-2, which meets the design requirements of the superconducting coil under this condition. The activity of magnet assembly is 3.33 × 10¹⁰Bq·kg^-1 when reactor is shut down, and after 10-year shut down, the activity reaches 6.14 × 10⁸Bq·kg^-1, which decreases two order of magnitude. Conclusively, the CFETR 3D model meets the preliminary design requirements and can provide some data support for the construction of CFETR. (authors)