Since the Deuterium Fluoride (DF) chemical laser utilizes a high-speed reacting flow with multiple chemical species, the choices of key species, reactions and rate constants have a great impact on the simulation result. Different types of DF chemical kinetic model are discussed, the simplified rules are given, and several simplified kinetic models are used in the numerical simulation of DF chemical laser. Through comparison between these results and the results under base kinetic model, the differences in the spatial distribution of small signal gains and DF (v) (v=0, 1, 2) are obtained. Finally, aimed at (NF3+H2+He)/D2 and “cold reaction” DF chemical laser system, an 11 species and 23 reaction simplified kinetic model is recommended, which can decrease computational costs and make the programming of reaction flowfield simulation more easier.