The transformation and development is an inevitable problem for resource-based cities (RBCs). In the process of transformation, cities in various cities, regions, resource types and development stages are having shown commonality and uniqueness. However, little work has been done on the horizontal comparison between RBCs. This paper evaluates the transformation level of 81 RBCs in China from 2006 to 2017 and investigates the transformation effect of cities in different regions, different dominant resources and different development stages. The comprehensive index system incorporating economy, society and environment is established by using the improved TOPSIS method. The results indicate that the transformation effects of most RBCs are between 0.400 and 0.800. Generally speaking, the transformation effects of four economic regions are on the rise, especially in the western region, with an increase of 17.626% from 2006 to 2015. The transformation effect of RBCs in the eastern region is the highest, while that in the northeast is the worst. Regeneration cities’ transformation effect is the best, reaching more than 0.70 in 2017. The transformation effect of growth cities is the worst, but the growth rate is the highest from 2006 to 2015. There is a rising trend of the transformation effects for oil-based cities and coal-based cities, while the transformation effects of iron-oriented cities and rare earth-oriented cities are not obvious.