Bulk alloys Nd1Ni5-xCx(x=0.0,0.1,0.3,0.5) are prepared by arc smelting and planetary grinding. X-ray diffractometer(XRD), Scanning electron microscopy (SEM), vibrating sample magnetometer (VSM), vector network analyzer(VNA) and other instruments were used to detect its structure, morphology and electromagnetic characteristics. The results show that, with the increase of C content, Ms and Hc of the sample tend to decrease, the absorption peak of electromagnetic wave moves to high-frequency, and two effective bandwidth (RL≤-10) appeared when the additive amount of C is x=0.5, respectively are 8.28~9.82 GHz and 11.17~12.03 GHz, which increases the applicable frequency band of the powder. In addition, With the change of the thickness, the frequency band with great impedance matching changes greatly, so that the reflection loss can be adjusted in the larger frequency band. Those change makes the powder has the possibility of wide application.