In work the results of an experimental research of optical spectra of nanocomposites based on superdispersed particles of iron, its compounds, and also high pressure polythene matrix are given. Samples were synthesized by the method described in and represented plates by thickness 0,4-0,5 mm made by a method of mechanical hot pressing. The transmission and reflection spectrums of samples were measured by standard two-beam spectrophotometer GARY 2415 type (firm VARIAN, USA). For exclusion of spatial dependence of reflected and transmitted beams intensity the measurements were carried out by integrating sphere relatively of the standard consisting the fine-dyspersated Ba2SO4. The transmission and reflection spectrums of nanocomposites in a range 400-1600 nm were measured depending on a percolation level of iron and its compounds in a matrix