Aiming at the performance degradation of atmospheric laser communication system due to atmospheric turbulence,the performance of atmospheric laser communication crossing-layer optimization system based on adaptive modulation coding (AMC) at physical layer and hybrid automatic repeat request (HARQ) at data link layer is investigated.Firstly,a turbulent channel model is established from the viewpoint of signal layer and verified by the filed experiments.On that basis,the atmospheric laser communication system model based on AMC and HARQ is established.Secondly,the formulas of packet error rate and bandwidth utilization are derived.Finally,it is simulated in dual Gamma channel model.Simulation results show that the atmospheric laser communication based on AMC and HARQ can greatly improve the system bandwidth utilization under the condition of ensuring a certain error performance and improve the system error performance when only single AMC is applied.With the increase of retransmission times,both the packet error rate and the bandwidth utilization rate are improved but the increase of bandwidth utilization decreases.