Abstract:As an important transportation hub city in the Qinghai-Tibet Plateau, Golmud's sustainable and healthy development of the ecological environments is closely related to the local economic prosperity and social stability of the related regions. Most studies on ecological change monitoring with long-time sequence remote sensing imageries often ignore the directivity in the selection of key time nodes among the long time series, and they usually take methods such as equal interval partition to select time nodes. Based on the above situation, we first calculated the 30 year sequence data of Remote Sensing Ecological Index (RSEI) of the city of Golmud on the Google Earth Engine (GEE) platform and we scientifically defined the time nodes of the study area by a nonparametric statistical method, the Mann-Kendall mutation test method, and then further analyzed the temporal and spatial variation characteristics of the ecological environment in the city of Golmud and in the end discussions were carried out to find out the main influencing driving factors. The results showed that, (1) the index of RSEI could be used to effectively evaluate the quality of ecological environments in the city of Golmud and similar areas. The average value of RSEI in the past 30 years was gradually changed from 0.38 to 0.33, and the overall changing trend of ecological environment was degradation; (2) through the Mann-Kendall mutation test, the year nodes of 1990, 2001, 2006, 2015 and 2019 were selected as the final time nodes of the study area. For the above five time nodes, the grades of the index of RSEI are mainly in the state of poor, accounting for more than 45% of the total area of Golmud, and the regions with the state of poor were mainly distributed in the northern part of the Qaidam Basin. The changing trend of the grade of the RSEI index was mainly decreased during the whole time series, which was most obvious in the time node of 2001 and the changing trend began to slow down in 2015; (3) affected by the climate and human activities at different degrees, the changing trend of the RSEI index in Golmud was mainly decreasing, which accounted for 89.73% of the total area, and which was widely distributed in the Qaidam and Tanggula Mountains areas, was greatly affected by climate factors; While areas with increasing trend took only 3.24% of the total area. The areas with increasing changing trend of the RSEI index were mainly distributed in the urban and town areas with intensive human activities in the city of Golmud, and the metallogenic belt of Qaidam Basin, which were greatly affected by human activities.