Abstract: Nanocrystalline nickel ferrite was prepared by polyacrylamide gel, taking acrylamide as monomer and N, N-methylenediacrylamide as lattice agent. FT-IR spectrometer, XRD, TEM and waveguide were used to characterize the gel, products and their electromagnetic properties after calcining. XRD patterns showed that the dried gel is amorphous, the spinel nickel ferrite formed at not lower than 400°C. The grain sizes and M-O characteristic absorption bonds are dependant on heat treatment temperature. When the calcining temperatures are 400, 600 and 800°C, the grain sizes are 8, 25 and 40 nm, respectively, as identified by TEM. The FT-IR spectra illustrated that the M-O characteristic absorption bonds shift from 590 cm² to 613 cm^-1. The nanocrystalline presents not only dielectric loss but magnetic loss in the frequency range of measurement, and both the losses of spinel-type nanocrystalline increases obviously with increasing heat treatment temperature.