The spatio-temporal evolution and the spatial effect analysis of land ecological efficiency (abbrev. eco-efficiency) are key to achieving high-quality economic, environmental and social development. It is also important to optimize territorial space layout and coordinate urbanization development as well as ecological civilization construction. Based on 287 cities at prefecture-level and above in China, we constructed an efficiency measurement index system using resource-capital-labor as the input index, economic-resource-social-ecological benefits as the expected output and carbon emissions as the unexpected output. Besides, Natural breaks, Exploratory Spatial Data Analysis, Trend Analysis and Standard Deviation Elliptic Model were conducted to delve into the spatiotemporal pattern and influencing factors of land eco-efficiency from 2005 to 2019. The results are as follows: (1) under carbon emission constraints, the average values of land eco-efficiency index were 0.82, 0.93, 0.87 and 0.84 in 2005, 2010, 2015 and 2019, respectively, showing a rising trend at first and a falling trend thereafter. Spatially, the difference goes from large to small in the western, eastern, northeast and central China. (2) The high-efficiency areas were concentrated around Chongqing and gradually extended to the northeast. The average efficiency areas were mainly distributed in the Pearl River Delta and urban agglomerations around the middle reaches of the Yangtze River. Low-efficiency areas were widely distributed in the central region of China.In the trend analysis, the spatial gradient pattern gradually evolved from “flat” to “high in the west and low in the east” in the east-west direction, and from “flat” to a gentle “U-shape” pattern in the north-south direction. (3) The spatial autocorrelation coefficient changed from negative to positive and the spatial agglomeration gradually changed to a positive correlation. The main significant correlation types were between High-High (abbrev. HH) areas and Low-Low (abbrev. LL) areas. Significant HH areas formed several groups in the northeast China and Inner Mongolia, and their number increases significantly. The significant LL areas formed a continuous distribution trend in the central and eastern China. (4) The standard deviation ellipse of land eco-efficiency always showed the trend of “northeast-southwest”, and the center of gravity moved significantly along Xiangyang-Nanyang-Luohe-Nanyang
