Electrochemistry of gallium hexacyanoferrate (GaHCF) as an analogue of prussian blue having a high-potential redox system was studied. A thin film of GaHCF was directly generated on a Ga substrate surface to fabricate a modified electrode. Electrochemical behavior of the modified electrode was studied at a typical cool environment of ca. 5degreesC. Although electrochemical activity of the electroactive film for ion insertion/extraction at this temperature is weaker than that at ambient temperature, the GaHCF film, however, showed excellent electrochemical activities. The redox potential of GaHCF was found to be higher than other transition metal hexacyanoferrates. The electroactive film formed on the electrode surface had an acceptable stability during both potential cycling and long-term usage. The results were indicative of the fact that GaHCF is a suitable modifier for the modification of electrode surfaces. On the other hand, the present work reports electrochemistry of an electroactive solid film with high-potential redox, and also well-defined electrochemical behavior of such systems, in a cool environment. (C) 2004 The Electrochemical Society.