The effect of laser jamming on photodetector from a long distance was influenced by the laser performances (laser power,wavelength,angle of divergence,et al) and the laser atmospheric transmission characteristics directly. The spectral response curve and the saturation threshold curve of power density of InSb photodetector were obtained by measurements. The atmospheric transmittance change curve with the laser wavelength under two specific transmission paths were analyzed by MODTRAN software. Combined with the development of mid-infrared laser,the atmospheric transmittance of several mid-infrared lasers was analyzed,and then the required power thresholds of the deuterium fluoride laser and optical parametric oscillator were calculated.