Combustion characteristics of dimethyl ether-air premixed mixtures were studied in a constant volume bomb. A two-zone model was proposed for predicting combustion parameters based on the pressure data. For a specified initial pressure, the mixtures around the stoichiometric equivalence ratio give the maximum pressure rise rate, the maximum mass burning rate, the maximum combustion pressure, and the maximum burned gas temperature. The shortest flame development duration and combustion duration occur around the stoichiometric mixture. A small difference in flame development duration and combustion duration within the three low initial pressures suggests that initial pressures of the mixture at low pressures have a small influence on the combustion duration.