When polycrystalline silicon detector is irradiated by 10.6 μm pulsed CO2 laser,the saturated threshold and damage thresholds of polycrystalline silicon are obtained through the experiments.Jamming effect was analyzed under the different laser energy densities.The damage mechanism was discussed,and jamming degree is graded.Through the relationship between laser energy and spot area,along with the restoration time of the detector,jamming effect of 10.6 μm pulsed CO2 laser on infrared imaging system is discussed under different jamming degrees.