Abstract: Islands’ special geographical location and multiple external disturbances have created their vulnerable ecosystems. Under the increasing interference of human activities, the heterogeneity of landscape pattern on islands has enhanced, thereby generating a series of ecological effects. In this paper, landscape indices were used to analyze the landscape pattern, and typical islands in the southern China, i.e. Dongshan Island and Nanao Island, were selected as the study area to explore the spatial heterogeneity of landscape pattern and its ecological effects. Ecological effect indicators in three aspects, including vegetation, soil, and heat-humidity conditions, were selected to analyze their response to the landscape pattern from the three scales: landscape, island, and grid. The results indicated that, at the landscape scale, the artificial landscape was significantly inferior to the natural landscape in all landscape indices and ecological effect indicators. At the island scale, despite the proximity of the two islands, the landscape pattern and ecological effects were quite different because of the differences in natural conditions and development orientation. The landscape pattern and ecological conditions on Nanao Island were all better than those on Dongshan Island. As for the grid scale, the landscape pattern and ecological effect indicators showed obvious spatial heterogeneity within the island. Altitude, slope and distance from shoreline showed significant positive correlation to vegetation indices, and negative correlation to soil and heat-humidity condition indices. The results revealed joint influences of natural contexts and human activities on the island landscape pattern and the responses of island ecosystems to the landscape pattern at different spatial scales. This study has practical implications for ecological restoration and spatial planning on islands.