Based on the detailed DF chemical kinetic models of two different fuel systems, the relevant simplified chemical kinetic mechanisms were presented with the method of sensitivity analysis. It is found that considering the DF “cold reaction” pumping reactions, ignoring DF higher excited vibrational states and omitting the recombination-dissociation reactions have little effect on the total system. The energy transfer reactions in DF and DF deactivations by D, D₂ and HF exhibits strong sensitivity to the chemical kinetics. Compared with the detailed mechanism, the simplified mechanism describes the general DF combustion process effectively, and at the same time reduces the species, element reactions and computational costs to a great extent. Therefore it fits more with coupling with three-dimensional flowfield numerical simulation code or software.