Abstract: Based on the thermal mechanism of laser ignition, a one dimension finite difference model has been developed to model the process of laser ignition.The laser ignition characters of B/KNO3/bakelite has also been simulated. Results show that with laser energy, laser power, laser energy density or laser absorption coefficient increasing, ignition delay time is prolonged,variation curve of surface temperature of the powder appears double peaks with laser energy approaching ignition energy threshold,and that ignition power threshold increases with beam semidiameter augmenting, while reduces with laser pulse augmenting. Simulation results are accord with actual rules of laser ignition and experimental outcomes on the whole.