Sustainable tourismization is a favorable development mode and pathway for the promotion of the coordinated development of the economy, society, and ecology. Based on the connotations of tourismization, a comprehensive evaluation index system of sustainable tourismization was constructed. This system consists of three dimensions: consumption tourismization, spatial tourismization, and industrial tourismization. The level, spatial, and temporal distribution characteristics, and differences in sustainable tourismization among China’s provinces from 2009 to 2018 were measured and analyzed using the improved entropy method, the Theil index, a spatial autocorrelation analysis, and other methods. It was found that the level of provincial sustainable tourismization in China has steadily increased over time, with the eastern region taking the lead. The overall differences and inter-regional differences in terms of the provincial sustainable tourismization level have generally decreased year-by-year. The intraregional differences within the eastern region were found to be the largest, and the rate of contribution of inter-regional differences to overall differences was shown to decrease gradually, while the rate of contribution of intraregional differences within the western region increased gradually. A positive spatial correlation in the provincial sustainable tourismization level was identified, and the spatial agglomeration effect showed an increasing trend. The spatial dependence was mainly characterized by “high–high” (HH) agglomeration, showing a ladder difference of “higher in the east and lower in the west”. The results of this study were used to identify where emphasis should be placed in terms of policy and strategy.