A comprehensive channel model for air ground optical communication is established for an uneven atmospheric environment with smoke and fog, and a discrete layered height model is used to analyze the differences between uplink and downlink communication. Experimental results indicate that a stable simulation can be achieved after reaching six layers of high layering. In an uneven atmospheric smoke and fog environment, optical signs passing through smoke near the ground can significantly reduce communication quality, in which the effect on the downlink is greater than that on the uplink. In general, the performance of the uplink is superior to that of the downlink. An increase in the receiving aperture affects the performance improvement of the uplink more significantly than that of the downlink. As the receiving diameter increases by 0.1 m, the bit error rate decreases by an order of magnitude. Increasing the receiving aperture degrades the communication performance of the downlink. Meanwhile, increasing the zenith angle deteriorates the communication performance of both the uplink and downlink. The results of this study can provide theoretical reference for air ground laser communication.