The properties of a Pt-10% Ph gauze catalyst, modified by coating its surface with alumina film containing dispersed platinum metals, have been studied. The conversion, process yield and morphological changes of the surface of the modified catalyst are compared with those of a standard gauze applied in the HCN synthesis. For the first time it has been demonstrated, basing on HRTEM observations, that formation of a Pt-Al intermetallic compound on the surface of the gauze catalyst occurs under the conditions of HCN synthesis by Andrussov’s method.