In this paper, we present the calculation results of the electronic structure and optical spectrumand an experimental study of the optical properties of Heusler alloys Mn2 – xFe1 + xAl (x = –0.5, 0, 0.5, 1).An anomalous for metallic systems behavior of the optical conductivity of alloys in the IR region of the spectrumwas found: the absence of Drude growth and a high level of interband absorption. This behavior is shownto be determined by the features of the electronic structure: the Fermi level is located in the region of highdensity of states that is formed by the d states of Mn and Fe.