Under the background of global change, the ecosystem of the Qinghai-Tibet Plateau has been affected and threatened by both nature and human activities, and the ecological risks are intensifying. The Qinghai-Tibet Plateau is a relatively independent geographic unit with a high average altitude and complex and diverse landforms. Its fragile alpine ecosystem is extremely sensitive to global climate change. In recent years, the population of the plateau has increased and the process of urbanization has accelerated, the scale and intensity of human activities have increased significantly, and ecological risks have increased. At present, the research results of ecological risk assessment are mainly found in local areas of the Qinghai-Tibet Plateau. This article, aiming at understanding the source of ecological risks, analyzes the spatial distribution of risks and their causes. The ecological risk assessment of the entire plateau is expected to provide references for the identification, management and early warning of regional ecological risks. We establish an ecological risk assessment index system for the study area, which includes 13 ecological risk source indicators, 10 ecological vulnerability indicators, and 7 ecological risk management capability indicators. Then we select the official remote sensing product data with a high spatial resolution, according to the characteristics of the data which are divided into numerical and non-numerical data. Using ArcGIS 10.2 to normalize the numerical data, according to the contribution rate to ecological risk, the non-numerical data are graded, and the ecological risk evaluation optimization model is used to comprehensively evaluate the ecological risk of the plateau. The results showed that: overall ecological risk of the study area is relatively low, with low and very low ecological risk areas accounting for 55.84%, extremely high risk areas being only 7.19%, high risk areas 11.95%, and medium ecological risk areas 25.02%, and the extremely low and low ecological risk areas account for more than half of the plateau area; medium ecological risk areas are mainly distributed in areas with high intensity of human activities. The impact of human activities on the eco-environment of the Qinghai-Tibet Plateau cannot be ignored; the extremely high-risk areas and medium-risk areas form a "C"-shaped pattern; the low-risk areas in the hinterland of the plateau have higher altitudes, severe cold climates, and fragile eco-environments, but the strengthening of ecological management measures has greatly reduced the ecological risk in the study area. The overall ecological risk of the Qinghai-Tibet Plateau is mainly controlled by natural factors, and the impact of human activities on the eco-environment cannot be ignored. The establishment of national nature reserves or national parks to protect the ecological environment can greatly reduce its ecological risks. It is necessary to pay special attention to areas with high intensity of human activities on the plateau, where their ecological risks have reached a medium intensity. Creating a new pattern of harmonious coexistence between humans and nature, and avoiding excessive human intervention in the eco-environment on the Qinghai-Tibet Plateau is an important way to reduce ecological risks in the future.