The Qinghai-Tibet Plateau is one of the most important units of China's "three regions and four belts" ecosystem protection and restoration projects, and balancing its ecological security and reasonable regional development is the basis for ensuring China's ecological stability. The coupling mechanism between regional development intensity and ecological security is explained. The coordination degree and fractal of the coupling between regional development intensity and ecological security on the Qinghai-Tibet Plateau from 2011 to 2020 was measured. The results show that:(1) the regional development intensity of the Qinghai-Tibet Plateau was increasing during the study period, with more than 90% of cities (states) increasing by more than 10%, and the spatial spillover from Xining and Lhasa as the double core was accelerating, leading to the expansion of the surrounding areas such as Haixi Prefecture and Linzhi, respectively. The ecological security index of each city (state) on the Qinghai-Tibet Plateau was on the rise, with more than 60% of cities (states) increasing by more than 10%, showing a pattern of belt-like depression in the central and western parts and vertical grouping in the east. The depression of ecological security index was moving to the southern edge of Xinjiang. (2) The coordination degree of coupling development intensity and ecological security of each city (state) on the Qinghai-Tibet Plateau increased to different degrees between 2011 and 2020. More than 50% of the cities (states) reached the light coupling category, and no cities (states) reached the high quality coupling category, But there were many cities (states)lagging behind in terms of development intensity or ecological security. (3) The pattern of coupling and coordination between development intensity and ecological security on the Qinghai-Tibet Plateau varied significantly, gradually forming three major groups from Xining, Bayingoleng and Lhasa-Western Yunnan (Lijiang, Diqing and Nujiang) gradually expanding to neighboring regions, forming a pattern of high in the east and low in the west, with multiple groups side by side. This paper reveals to a certain extent the correlation between the spatial and temporal distribution of regional development intensity and ecological security on the Qinghai-Tibet Plateau, which can provide a basis for the regulation of human activities in the construction of ecological security barriers at the city (state) level on the Qinghai-Tibet Plateau.