A twodimensional model was used to simulate the chemical dynamic process, gas dynamic process and lasi ng process of a combustiondriven CW HF overtone chemical laser. The calculated results included reaction product in combustor, HF molecule concentration on each vibration energy level while lasing, average pressure and temperature in the cavity, zero power gain coefficient, laser spectrum, output power, and chemical efficency. Compared with HF fundamental lasers, the results were analyzed．