通过分析卫星遥感数据，得出淇澳岛海岸冲淤变化情况，推演出其变化趋势，探究其多方面的地理原因。通过目视解译提取海岸线信息，综合现场调查与最新高空间分辨率卫星地图等对解译结果以修正。结果显示，西部海岸线向海扩张而呈现淤积态势，原因主要是红树林面积的增加。东部海岸线基本保持稳定，此处存在较为明显的侵蚀与堆积作用，交互影响，处于较为平衡的状态，还与海岸线曲折变化与人工建筑有关。东北部海湾海岸线向陆前进而呈现冲蚀态势，与珠江水动力有关，而其内部海岸线局部变化与海岬遮挡作用有关。西部海岸线在2003年之后明显向海扩张，与红树林自然保护区的建立有关。东北部海湾海岸线向陆前进的趋势在变缓，与人为因素有关。近25年淇澳岛海岸线长度总体上在增加，并呈现继续增加的趋势。

By analyzing satellite remote sensing data, we can obtain the changes in coastal erosion and sedimentation on Qi'ao Island, deduce its trend, and explore its multifaceted geographical reasons. Extract coastline information through visual interpretation, and revise the interpretation results by combining on-site investigations with the latest high-resolution satellite maps. The results show that the western coastline is expanding towards the sea and showing a siltation trend, mainly due to the increase in mangrove area. The eastern coastline remains basically stable, with significant erosion and accumulation, interactive effects, and a relatively balanced state. It is also related to the tortuous changes in the coastline and artificial buildings. The coastal line of the northeast bay moves towards the land and presents an erosion trend, which is related to the hydrodynamic force of the the Pearl River, while the local change of its internal coastline is related to the shielding effect of headlands. The western coastline has significantly expanded towards the sea since 2003, which is related to the establishment of mangrove nature reserves. The trend of the coastline of the northeastern Gulf advancing towards land is slowing down, which is related to human factors. In the past 25 years, the length of the coastline of Qiao Island has generally increased and continues to increase.