This study mainly investigates the environmental efficiency of 267 Chinese cities from 2004 to 2012 through a metafrontier, directional and super-efficiency approach. First, we explore the regional and time heterogeneity of environmental efficiency. Then, we compare the technological gap ratio in different regions and years. Lastly, we analyze the technological and management potential in different regions. We determine that the gap between environmental efficiency under group frontier and metafrontier widened from 2009 to 2012, indicating that environmental efficiency varies in different regions in China. The technology gap ratio has decreased in the four regions. This result confirms that the regional heterogeneity of environmental efficiency has increased. Thus, strengthening environmental management is crucial. China must improve green innovation to decrease energy consumption and abate carbon emissions.