The study of urban land use efficiency is of great significance for optimizing the spatial allocation of urban land, thereby promoting the intensive use of urban land and the transformation of economic development modes. Taking the Yangtze River Economic Belt (YREB) as the study object, we chose the undesirable Slacks-Based Measure (SBM) model to calculate the urban land use efficiency (ULUE). Then, we utilized the spatial correlation analysis and econometric methods to discuss its spatio-temporal features and influential factors. The results show the following: (1) The urban land use efficiency in the YREB steadily improved from 2010 to 2022, but the inter-regional efficiency gap evidently increased. (2) There is an efficiency value to be found in a multi-center network structure, and it forms a “core-periphery” distribution pattern. The high-efficiency areas in the downstream and upstream regions of the YREB are gradually increasing, while the efficiency value in the midstream area remains low. (3) The urban efficiency values have strong correlation, and they are mainly “High-High agglomeration” and “Low-Low agglomeration”, and they show significant regional characteristics. (4) The economic level, industrial structure, and urbanization have obvious motivating effects on ULUE, and the positive spatial spillover effect is clear. The foreign direct investment and land finance hinder the boost of efficiency, and the latter has a negative spatial spillover role on the ULUE in the downstream cities.