The way of preparation of the nanopowdered iron with the protective iron oxide coat by the reduction of nanopowdered crystalline or amorphous precursor of iron oxides and oxihydroxides in the reduction atmosphere, characterized by the fact that in the course of synchronous exhaust of secondarily originating gas products, nanopowdered crystalline or amorphous iron oxide or oxihydroxide with particle size smaller than 20 nm is thermally decomposed in the reduction atmosphere at temperature higher than the minimum decomposition temperature for the given oxide or oxihydroxide and hereby formed nanopowdered iron with the protective iron oxide coat, for example FeO, is cooled in the inert atmosphere, in the process of which nitrogen, argon or another inert gas is selected as the inert atmosphere.