Abstract: Using 105 islands along the southeastern coast of China as the study area, this study integrated multi-source species distribution and geographical attribute data to compare and analyze the α- and β-diversity patterns of native and invasive Lepidoptera species, and employed regression methods to quantify the impacts of island attributes (area and isolation) on these diversity patterns. The results indicated that the α-diversity patterns of Lepidoptera exhibited spatial heterogeneity: Taiwan Island and Hainan Island showed the highest species richness but low evenness, while small islands in the Zhoushan Archipelago displayed the lowest richness but high evenness. The community diversity of invasive species was lower than that of native communities, and certain islands presented a community structure highly concentrated on a single dominant species, making them prone to forming single dominant populations. Regarding β-diversity patterns, the overall dissimilarity of Lepidoptera communities among islands was remarkably high; the Zhoushan Archipelago exhibited high internal similarity but high external dissimilarity, and the overall community differences were dominated by species turnover. The mechanisms through which island geographical attributes affected native and invasive Lepidoptera diversity patterns exhibited consistency. The impact of area on the α-diversity patterns of both native and invasive Lepidoptera aligned with the classic Theory of Island Biogeography (TIB), with the area effect on invasive Lepidoptera simultaneously fitting the Exotic Species Theory of Island Biogeography (ES-TIB); however, isolation had a weak effect on α-diversity and primarily acted on the species turnover component of β-diversity, which differed from ES-TIB predictions. This discrepancy is presumably driven jointly by factors such as the moderate dispersal capabilities of Lepidoptera, the legacy effects of the geological history of land-bridge islands, and human-mediated dispersal. The study reveals that island area is significantly positively correlated with Lepidoptera α-diversity, and isolation is significantly correlated with β-diversity, validating the applicability of TIB and ES-TIB to lepidopteran insects on the islands along the southeastern coast of China, and providing a scientific basis for the hierarchical prevention and control and ecological risk early warning of Lepidoptera invasions in these regions.