The addition of manganese into Nd9Fe85-xMnxB6（X=0,0.5,1） was found to enhance the magnetic properties of a -Fe/Nd2Fe14B magnets. After optimal annealed, the coercivity and remanence ratio increased from 0.34MA/m to 0.4MA/m and from 0.70 to 0.72, respectively, for the increase of x from 0 to 1. The XRD patterns indicated the addition of manganese could promote crystallization of as-spun samples. Moreover, the XRD spectra showed almost same grain sizes obtained for the optimal annealed samples. Thermomagnetic analysis (TMA) measurement indicated that the doping of Mn reduces the Tc of the Nd2Fe14B phase and raises that of a-Fe phase in the system. It is believed the exchange coupling between the Nd2Fe14B phase and a-Fe phase was partly changed by Mn addition, which is the reason for the enhanced magnetic properties and the change of Tc.