Abstract: After acidification, sensitization and activation of multi-carbon nanotubes(CNTs), Ni-coated CNTs (Ni-CNTs)were produced by electroless plating through ultrasonic spray atomization. The obtained CNTs were characterized by TEM, EDS and Raman spectra. The results show that a continous and uniform Ni-plating layer is obtained. And the dispersion of CNTs in the product has been improved, which makes Ni-CNTs more conducive in the application area of composite materials. It is found that the different microstructure of the Ni plated absorbing properties of carbon nanotubes have obvious difference. For the Ni plated CNTs with relatively thin coatings, the maximum microwave absorbing peak of the Ni-CNTs is -17.12 dB at 9.36 GHz, the band width is 5.28 GHz (R<-5 dB) and 2 GHz (R<-10 dB), which is contributed to manufacturing broadband composite absorbing materials.