Abstract: An accurate grasp of the evolution of regional ecological environment quality is of great practical significance to achieve harmonious and stable highquality development of human society and nature. Here, we used four periods of Landsat TM/OLI remote sensing images of Ningxia in 2000, 2006, 2012, and 2018 as data sources to extract generalized difference vegetation index (GI), moisture index (WI), desertification index (DI), salinization index (MSI), and construct remote sensing ecological distance index (RSEDI) to analyze the spatial and temporal evolution of Ningxia ecological environment and its driving factors. The results showed that the GI values generally showed an increasing trend from 2000 to 2018, which was 0.265, 0.246, 0.286, and 0.288 in 2000, 2006, 2012, and 2018, respectively. The WI, MSI, and DI  values generally showed a decreasing trend, with WI values being 0.212, 0.223, 0.159 and 0.168, MSI values being 0.218, 0.242, 0.196 and 0.202, and DI values being 0.190, 0.183, 0.180 and 0.184 in those four years, respectively. The overall trend of RSEDI index was increasing, with the mean values being 0.428, 0.379, 0.417 and 0.438 in those four years, respectively, indicating an improved ecological environment. There were significant spatial variations in ecological environment quality of the study area. The GI and WI had the distribution characteristics of high in north and south and low in middle, with the high-value areas located in the Yinchuan Plain and southern mountainous areas and the low-value areas located in the central arid area. The high-value areas of DI were distributed in the east, west, north, and central areas, while the lowvalue areas were distributed in the Yinchuan Plain and southern mountainous areas. The high-value areas of MSI were mainly distributed in the Yanghuang irrigation area of central part and the Yinbei irrigation area of northern part, while the low-value area was located in the southern mountainous area. In general, desertification and salinization were lower in the southern mountainous area, higher in the central area, and highest in the northern Yinchuan Plain. Human factors had the greatest contribution (51.4%), with the main driving factors of total population, urbanization rate, primary industry, secondary industry and tertiary industry output values. The natural factors were the second important type with a contribution rate of 35.5%, with mean temperature, mean wind speed and potential evaporation as the main factors.

Key words: ecological environment quality, remote sensing ecological distance index, temporal and spatial variation, contribution rate, Ningxia.