Ignition delay time measurements of dimethyl carbonate (DMC)/n-heptane blends have been studied in a shock tube in the temperature range of 1100-1600K, at different equivalence ratios (0.5; 1.0; 2.0), pressures of 2.0 and 10.0atm, and with mole fractions of DMC in the fuel blends varying from 0% to 100% (0%; 20%; 80%; 100%). A detailed model of DMC/n-heptane was constructed to simulate the ignition process of neat and blended fuels. The effect of equivalence ratio on the ignition delay time of fuel blends was found to be increasingly weak with an increase in DMC addition. Reaction path analysis was conducted to explain the equivalence ratio effect. The concentration of the radical pool increased during its buildup stage at higher temperatures as DMC addition increases, leading to an enhanced chemical reactivity in the reaction system. The opposite observation at lower temperatures was interpreted by the methyl ester moiety.