Landsat MSS/TM/OLI images from 1975 to 2015 were used as main data sources to derive the spatiotemporal patterns of ecosystems in Ningxia Hui Autonomous Region. The amplitude, rate, transition types, and regional differentiation of the spatiotemporal changes and human activity disturbance of the ecosystem in Ningxia over the past 40 years were analyzed using the annual net area change rate, transfer matrix, and the land development degree comprehensive index, thus the spatiotemporal changes of the ecosystem patterns in the study area and its regional heterogeneity were revealed finally. The results showed that (1) farmland and grassland accounted for more than 75% of the total area and showed a negative correlation between their area change trends. Over the last 40 years, forestland, artificial surface, and farmland showed net increases of 477.5 km², 884.6 km², and 209.8 km², respectively, while grassland, wetland, and desert showed net decreases of 115.5 km², 69.4 km², and 1387.0 km², respectively. (2) The result of ecosystem transition matrix indicated that about 6% of the ecosystem area in the whole district had changed over each period. The three main conversion types were the mutual conversions between farmland and grassland, the transfers from grassland and desert to farmland, and the transfers from farmland to grassland and artificial surface. (3) The degree of human activity disturbance continued to increase in the northern region, and land development effects were most pronounced in Jinfeng District, Xixia District and Yongning County, while the central region showed a slight reduction, and the southern region showed a significant reduction, indicating that human activities had greater disturbance to the ecosystems in the northern and central parts of Ningxia.