Abstract Phase composition, structure parameters and basic magnetic characteristics obtained by the sol-gel combustion nanopowders of copper ferrite spinel CuFe2O4 are investigated. The values of the fields of magnetocrystalline anisotropy were determined by the FMR method. The comparison of properties of synthesized materials is done: the sample No 1 – immediately after the combustion of the gel, the sample No 2 – after annealing at 623 K for four hours and the sample No 3 – after annealing at 1073 K for four hours. The thermal treatment leads to the increase in the concentration of the phase with tetragonal crystal structure. Particle sizes and the values of anisotropy fields of this phase also increased. The value of the saturation magnetization varies slightly after annealing.