A series of alpha-Mo2C/gamma-Al2O3 catalysts with different Mo loadings were prepared by temperature-programmed reaction and characterized by X-ray diffraction, BET specific surface area determination, and NH3 temperature-programmed desorption. Their ability to decompose hydrazine was tested using a thruster and a microreactor. The catalytic activity for hydrazine decomposition of the fresh alpha-Mo2C/gamma-Al2O3 catalyst is higher than that of the passivated alpha-Mo2C/gamma-Al2O3 catalyst. The catalytic activity also decreased with the reaction time at 303 K, and the deactivation is mainly due to strongly adsorbed NHx species. Flushing with N-2 at 773 K recovers the activity of the catalyst. It was shown that hydrazine decomposes to NH3 and N-2 at low temperatures, and the produced NH3 dissociates into N-2 and H-2 at elevated temperatures.