Abstract: The neutron spectrum parameters of the miniature neutron source reactor（MNSR） in China Institute of Atomic Energy were measured by bare monitor method using Au， Zr and Fe as monitors. The measured values of α（a parameter accounting for the nonideality of the 1/E epithermal neutron fluence rate distribution）， f (thermal / epithermal neutron fluence rate) and f_F (thermal / fast neutron fluence rate) in the inner irradiation site are －0.007±0.003， 20.8±0.4， and 5.5±0.2， respectively. The value of φ_th measured by this method is agreed with that measured by 4πβ-γ method within 2%. Compared with SLOWPOKE, MNSR had higher values of αand f_F. The comparison with the previous measurements indicates that MNSR has a quite constant neutron spectrum. The fluence rate monitors are not needed when k₀ NAA is performed by using MNSR as neutron source， and with occasional check, the comparator data from one measurement may be used as a standard for subsequent analyses over a period of time.