The melt-spun ribbons of Nd8Fe85Mo1B6 have been prepared by directly rapid quenching at different wheel speeds. From the result of vibrating sample magnetometer measurement, we found that the magnetic properties of the ribbons are dependent on the wheel speed. X-ray diffraction and thermomagnetic analysis were also used to investigate microstructure and phase composition of the samples. The result shows that the TbCu7 phase increases with increasing wheel speed; at the same time, a decreased grain size of the α-Fe phase is observed. The change of magnetic properties is due to the change of phase composition and grain size of the samples.