Abstract: Improving the industrial ecologicalization level is an important measure for the Yangtze River Economic Belt (YREB) to implement the strategy of “step up conservation and stop over development” and take the road of “ecological priority and green development”. Based on the connotation and characteristics of industrial ecologicalization, the evaluation index system of municipal industrial ecologicalization level was established in this study. In addition, the overall entropy method, exploratory spatial analysis method and spatial econometric model were used to dynamically evaluate the industrial ecologicalization level and analyzed its spatial-temporal evolution characteristics and the associated influencing factors. A total of 108 prefecture-level cities were selected in this paper in the YREB from the period of “11th Five-Year Plan” to “13th Five-Year Plan” (2006-2020). The findings were as follows: (1) The overall industrial ecologicalization level in the YREB increased year by year. The score rose from 0.374 in 2006 to 0.505 in 2020, with an average annual growth rate of 2.17%. (2) Regional differences of the industrial ecologicalization level in the YREB were apparent, showing a spatial differentiation pattern of “high in the east and low in the west” as a whole, with the features of hierarchical and stage evolution. (3) The industrial ecologicalization level in the YREB demonstrated significant spatial correlation characteristics. The high-high agglomeration areas were all distributed in the downstream cities, while the low-low agglomeration areas were scattered in the midstream or upstream cities. (4) Economic development, industrial upgrading, government regulation and urbanization could promote the improvement of the industrial ecologicalization level of city itself, while the industrial structure and environmental regulations would inhibit the level. (5) Under the indirect effect, economic development, industrial upgrading, industrial structure and technological innovation might promote the improvement of the industrial ecologicalization level of neighboring cities, while government regulation and foreign investment would pose an effect of inhibition.