Abstract: Cumulative impacts of construction and operation of the Qinghai-Tibet Railway on ecosystem were studied using Eco-function deviation cumulative index, landscape disturbance cumulative index, vegetation degradation cumulative index, ecological blocking cumulative index and regional ecological cumulative effect index with the aid of the remote sensing and GIS technology and on the basis of relevant research results available. Results show that the construction and operation of the railway does have some cumulatve effects on the ecological service function, landscape pattern, vegetation coverage and ecological flow of the direct impact zones, 0-1 km wide alongside the railway. Its impacts on landscape pattern and ecological flow are were the most significant and more on the Lhasa - Tanglha section than on the Tanglha ~ Golmud section, and are demonstrated mainly in farmland, grassland, river wetland and desert ecosystems. In terms of indirect or synergic cumulative impacts on the >1-5 km and >5-10 km wide zones alongside the railway, the Lhasa - Tanglha section is more significant than the Tanglha -Golmud section. Some negative effects are observed on the farmland, desert and river ecosystems in the two zones, especially the farmland ecosystem, in the form of disturbance and alienation as a result of the expansion of Lhasa and Gormud.