Gas-sensitive properties of y-Fe205 thin film, deposited on Si-substrate of new design, have been studied in this work. The layers were formed by using sol-get derived y-Fe203xnH20 colloidal solution Structural features of the films and peculiarities of iron state were obtained by employing XRD, HR-TEM, IR and Mossbauer spectroscopy. High sensitivity of the mentioned sensor to CH4 has been established.