In this paper, the AOS effective throughput rate is analyzed firstly. Then, in order to improve the effective throughput rate, a scheme of AOS cross layer transmission system is presented. In the proposed scheme, based on the space channel state, the dynamic optimization parameters of AOS Space Date Link Protocol sublayer and AOS Sync and Channel Coding sublayer are selected. Then the switch thresholds are presented. Finally, the effective throughput rate of the proposed AOS cross layer transmission system is simulated. Simulations show that the throughput rate can be optimized effectively.