The Qinghai-Tibet Plateau is the highest plateau in the world. The complex and diverse geomorphological structure restricts human engineering activities to a certain extent, and human engineering activities will have impacts on the fragile and sensitive ecological environment of the Qinghai-Tibet Plateau. Based on data from energy engineering, social and economic development, transportation network, and other fields, combined with the field investigation of the Qinghai Tibet Plateau scientific research, this paper aims to establish a set of index system for evaluating the intensity of human engineering activities on the Qinghai-Tibet Plateau at the county scale. Using the analytic hierarchy process (AHP) and expert scoring method, and combined with various spatial analysis methods to assign weights to each index factor, the spatiotemporal changes of human engineering activity intensity in the Qinghai Tibet Plateau in 2000, 2005, 2010, 2015, and 2020 are explored at county-level unit. The paper comprehensively and scientifically evaluates the evolution characteristics of the spatio-temporal pattern of the intensity of human engineering activities on the Qinghai-Tibet Plateau. The results show that: 1) The quantitative evaluation index system established in this paper based on three primary indicators: energy engineering construction intensity, municipal infrastructure construction intensity, and transportation infrastructure construction intensity, as well as 10 secondary indicators and 19 tertiary indicators, can well reflect the spatial differentiation of human engineering activity intensity in the research area. 2) The evaluation shows that the overall intensity of human engineering activities on the Qinghai-Tibet Plateau is increasing during 2000-2020, and the growth rate is accelerating. 3) The intensity of human engineering activities on the Qinghai-Tibet Plateau differs significantly between the east and the west. Influenced by factors such as resource allocation and population distribution, Xining and Lhasa have obvious advantages in economic development and infrastructure construction. In terms of human engineering activity intensity, they exhibit an irregular decreasing spatial pattern outward from the central region centered on the "Xining Lhasa" axis. 4) The increase in the intensity of human engineering activities is closely related to the rapid urbanization development and the expansion of the scale of engineering construction in the Qinghai-Tibet Plateau region. With the promotion of economic and social development, energy demand and infrastructure construction continue to grow, which makes human engineering activities in the Qinghai-Tibet Plateau region continue to increase, indicating that its impact on ecology is also gradually increasing. In vigorously developing energy and construction projects, we should focus on and protect the ecological environment.