To assess the level of provincial ecological civilization development in China, this work constructs an evaluation index system that includes four areas, 10 targets, and 25 specific indicators. Based on a comparison and improvement of existing data standardization methods, this study puts forward a double-benchmark progressive method as the standardization method, and adopts the comprehensive weighted-index method to evaluate the ecological civilization development level of China's 31 provinces (including provinces, autonomous regions, and municipalities). The results indicate that the ecological civilization development level in China is low, and that the ecological civilization development level of the southeastern coastal areas is higher than those of Central and Western China. In general, gaps still exist between China’s ecological civilization development level, its expected level, and the global level. Although China has made remarkable achievements to date in terms of overall economic and social construction, it is necessary to further strengthen and pay attention to ecological environmental protection, industrial pollution control, industrial optimization, and efficient resource use.