A new type of Ni-coated strontium ferrite powder was prepared with electroless plating enhanced by ultrasonic wave at room temperature. The morphology, crystal structure and microwave absorption properties of the Ni-coated powder were investigated with field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), EDS and vector network analyzer. The results show that the powder possesses excellent microwave absorption properties. The maximum microwave loss of the composite powder reaches -41.3 dB. The bandwidth with the loss above -10 dB reaches 8 GHz.