The effects of pressure and triethyleneglycol dinitrate (TEGDN) content on the decomposition reaction mechanism and kinetics of the double-base (DB) gun propellant composed of mixed ester of TEGDN and nitroglycerin (NG). and nitrocellulose (NC) were investigated by high-pressure differential scanning calorimetry (PDSC). The results show that the high pressure can decrease the DSC peak temperature, increase the decomposition heat; with the increase in the content of TEGDN, the decomposition heat decreases below 2 MPa and rises at 4MPa. The high pressure can change the decomposition reaction mechanism and the kinetics of the DB gun propellant under 0.1 MPa: the high TEGDN content does [lot change the mechanism functions, and the kinetic equation has a little difference between the sample and the control propellant: the high pressure makes the critical temperature (T-be) of thermal explosion of the sample decrease, while the high TEGDN content make it present a increasing trend, and the DB gun propellant containing high content of TEGDN has a better thermal stability. Crown Copyright (C) 2008 Published by Elsevier B,V, All rights reserved.