The Tb9Fe88Cr3 alloy powders were prepared by the arc melting method and high energy ball milling. The phase structure and the microstructure of the alloys powders were analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Then their microwave absorbing properties were analyzed by a vector network analyzer. The results show that the absorbing properties of the powders with micro-oxidation treatment at low frequency are better than that in raw state. On the basis of micro-oxidation treatment, the powders were dealt with by vacuum heat treatment at different temperatures. When the vacuum heat treatment temperature is 350 °C, the absorption peak value of the powders reaches –11.5 dB at 7 GHz. As the temperature of vacuum heat treatment increases, the absorption peak shifts towards the lower frequency region, and the reflectivity increases. When the vacuum heat treatment temperature is 450 and 550 °C, compared to that of the sample only dealt with by micro-oxidation treatment, they have similar absorption frequency, the absorption peak value decreases by 2~3 dB, and the absorbing properties at low frequency region are improved further