In this work, the effects of neutron irradiation and high temperature on the magnetic properties and structure of Sm2Co17 permanent magnets (PMs) were investigated. The phase composition in Sm2Co17 PMs does not change after neutron irradiation with fluence of 5 × 1014n/cm2. The magnetic domain structure and Mössbauer spectra of Sm2Co17 PMs were almost kept the same after neutron irradiation. The neutron irradiation almost does not influence the intrinsic coercivity and magnetic flux ϕ of Sm2Co17 PMs. When temperatures increase from room temperature to 300 °C, intrinsic coercivity Hcj, remanence Br and maximum energy product (BH)max have 52.8 %, 5.6 % and 15.4 % deterioration, respectively. Magnetic flux ϕ decreases by 4.1 %. When temperature increases to 550 °C, compared with room temperature, Hcj, Br and (BH)max decrease 88.8 %, 21.8 % and 54.3 %, respectively. ϕ has a 40 % deterioration.