Abstract: With the rapid development of China’s economy and marine technology, marine communication technology has become a key industrial field, showing significant potential in cross-domain communication. The design of a small buoy communication system, based on the third-generation BeiDou satellite module, should be aimed at boosting the cross-domain communication success rate while meeting the critical constraints of compact size, low power consumption, and minimal computational requirements. However, under high sea states the low antenna emergence height of the small buoys leads to frequent wave occlusion severely degrading signal stability during transmission. To overcome BeiDou communication instability under such conditions, this study proposes an intelligent self-adaptive technique integrating real-time buoy state monitoring and a dynamic trajectory prediction algorithm. By precisely monitoring current buoy states and accurately forecasting future heave motion trajectories, this technique controls optimal transmission windows, thereby improving success rates. Based on this methodology, hardware/software systems were developed and prototype buoys were tested using a laboratory apparatus simulating various sea states. Experimental results demonstrate uplink success rates of 100%, 94%, and 93% for sea states 3, 4, and 5 with downlink rates at 80%, 72%, and 75%, respectively. Thus, this solution can be applied to the communication systems of many small marine devices.