Due to the ongoing structural transformation in China, the service sector now constitutes approximately half of the total Chinese output. At the same time, the internal structure of this sector continues to change rapidly with the level of Chinese development. We analyze the impact of changes in the structure of Chinese service sector on the unified efficiency of Chinese service sector considering the energy consumption and carbon dioxide emissions. The non-radial directional distance function and the global data envelopment analysis method are combined to measure the unified (technical, allocative, operational and environmental) efficiency of Chinese service sector at both regional and sectoral levels. The results indicate that the financial sector and the sector of transportation, storage and post are the industries with the highest and lowest unified efficiency respectively. There exist differences across industries and regions in the unified efficiency of the service sector. As a second stage, a panel Tobit regression is processed to examine the effect of service structure on the unified efficiency of the service sector, in which a significant impact appears to exist. Promoting economic development and enhancing investment in research and development are beneficial to improving the unified efficiency of the service sector.