The cross sections for ~(169)Tm(n,xn)~(168,167,166,165)Tm reactions in intermediate energy region are useful for neutron field monitor, safety design consideration and material damage research for fusion material irradiation test and the radioactivities induced in components of accelerator. The evaluation of activation cross sections of (n,2n) reaction for ~(169)Tm has been performed below 20 MeV. In our evaluation, the identification and correction have been made to the differences and discrepancies among the existing activation cross sections from different laboratories to obtain more accurate da The cross sections for ~ (169) Tm (n, xn) ~ (168,167,166,165) Tm reactions in intermediate energy regions are useful for neutron field monitor, safety design consideration and material damage research for fusion material irradiation test and the radioactivities induced in components of accelerator. The evaluation of activation cross sections of (n, 2n) reaction for ~ (169) Tm has been performed below 20 MeV. In our evaluation, the identification and correction have been made to the differences and discrepancies among the existing activation cross sections from different laboratories to obtain more accurate da