Some low temperature gas-generating compositions, comprised of guanidine nitrate (GN), basic cupric nitrate (BCN), and ferric oxide (Fe2O3), were studied herein. The thermal decomposition properties and burning characteristics of GN/BCN/Fe2O3 mixtures were investigated by thermogravimetry/differential scanning calorimetry (TG/DSC), burning temperature measurements, automatic calorimetry, and X-ray diffraction (XRD). This study showed that the maximum burning temperature of GN/BCN/Fe2O3 mixture (613 degrees C) was 31% lower than that of GN/BCN mixture and the corresponding heat of combustion (2647Jg(-1)) decreased by 15%. When the GN/BCN/Fe2O3 mixtures were burning, Fe2O3 did not directly react with GN but with Cu (or CuO), which was produced by reaction between GN and BCN. The combustion process of GN/BCN/Fe2O3 grains could be divided into four stages: pre-heated, condensed, combustion, and cooling.