Abstract: Based on the Shannon classical communication theory, the atmospheric modulation model of wireless laser communication was investigated for enhancing wireless laser communication adaptability of the atmospheric channel. Firstly, the conversion relations of SER and BER was discussed, from error theory perspectives analysis atmospheric optical wireless communications. Afterwards，by analyzing Shannon limit communication rate of wireless laser communication in atmospheric channel, the importance of atmospheric channel bandwidth gradually came out. On the basis of this, an efficiency pulse state-interval coded modulation was present and its characteristics were estimated. Finally, the feasibility of the PSIM and the importance of atmospheric channel bandwidth to wireless laser communication were proved by wireless laser communication experiment in the hostile environments, At the end, a prospect was pointed out that atmospheric channel properties feedback technique in real time might be a key and precondition in all-weather wireless optical communication.