Electromagnetic (EM) wave absorbing materials with superhydrophobic property and enhanced microwave absorbing ability are very important for the application of stealth technologies, especially in humid conditions. In the present work, the electrospinning technique was employed to fabricate NiAc/PVA nanofibers (NFs) from nickel acetate tetrahydrate (NiAc) and poly(vinyl alcohol) (PVA) solution as precursors, while the PVA component was further pyrolyzed and carbonized to obtain Ni/NiO/C NFs. Microwave absorption performance and EM parameters of the prepared NFs were then investigated from 2.0 to 18.0 GHz. Comparative studies between different samples elucidated not only the possible causes for lose mechanisms, but also impedance matching. According to the experimental results, when NiAc/PVA NFs contained 8% NiAc, the calcinated Ni/NiO/C NFs could achieve an optimum reflection loss of − 33.9 dB at 10.4 GHz under a thickness of 2.5 mm and exhibit an effective frequency bandwidth of 5.7 GHz. Furthermore, the membrane of Ni/NiO/C NFs with the best absorption property exhibited robust hydrophobicity and the contact angle was 144.9°, It shows that the obtained Ni/NiO/C NFs have a broad application prospect in waterproof stealth materials. © 2019, Springer Science+Business Media, LLC, part of Springer Nature.