The noise types of photoconductive HgCdTe detector which is used to detect long-wave infrared are analyzed, and corresponding noise models are established. Combined with light intensity distribution models under different atmospheric turbulence conditions, the bit error rate expression of long-wave infrared wireless laser communication system is obtained when we use the digital pulse interval modulation mode. On the basis of selecting typical simulation data, the numerical simulation analysis for the bit error rate of long-wave infrared wireless laser communication is carried out with different atmosphere turbulence intensities, communication distances, transmission rates and average transmission powers. The results show that the long-wave infrared has the strong ability to resist the atmospheric turbulence, and the bit error rate can be satisfied when we choose proper transmission power and transmission rate.