Abstract: Scientific assessment of landscape vulnerability in intertwined region of plateau and plain is of great significance for regional ecological regulation．Based on land use/cover（LUCC）data of Tianshui City of several periods, a vulnerability assessment model based on landscape index was constructed to explore spatial and temporal distribution pattern, regional differences and changes of landscape vulnerability under the optimal grid．Results showed that optimal grid for landscape vulnerability analysis in Tianshui City was 4 km×4 km．From 1990 to 2020, there were significant changes in landscape types in Tianshui City, with main landscape types being farmland, forest, and grass．Growth rate of construction land area was the fastest, with more farmland area transferred out, and the rest of area converted to each other．Overall trend of landscape vulnerability was decreasing, with higher and medium fragility being main levels．The area transfer of vulnerability level was mainly based on adjacent levels, with less cross level transfer and smaller transfer area．There was a significant positive correlation in space, with little change in local spatial autocorrelation patterns and strong stability in spatial distribution．Based on vulnerability characteristics at different levels, countermeasures and suggestions were proposed for management of potential environmental hazards and restoration of ecological environment in Tianshui City in the future．