Manganese　(MnFe2O4)　nanoparticles　are　prepared　via　a　facile　solvothermal　method.　The　electromagnetic　properties　are　investigated　in　1-18　GHz,　indicating　the　MnFe2O4　nanoparticles　are　the　promising　materials　to　be　applied　as　microwave　absorbers.　The　wave　absorbing　mechanism　can　be　attributed　to　the　dielectric　loss,　magnetic　loss,　and　the　synergetic　effect.　The　permittivity　dispersion　behavior　is　explained　by　Debye　dipolar　relation　expression.　The　complex　permeability　is　analyzed　using　Landau-Lifshitz-Gilbert　equation.　Natural　resonance,　exchange　resonance,　and　eddy　current　loss　arise　at　different　frequencies.　(c)　2015　AIP　Publishing　LLC.