In order to make a reasonable evaluation on operating environment and energy efficiency in city tunnel， the distribution of CO concentration in different types of city tunnels has been studied. Three typical city tunnels have been researched， the main parameters of their operating environment have been tested， the electricity consumption has been stated. Operating environment and energy efficiency of different tunnels have been analyzed. Principal component analysis has been used to establish a theoretical model of evaluation of operating environment and energy efficiency， a comprehensive assessment has been conducted. Relatively optimal operating mode of the tunnel has been gated. This conclusion has a certain reference value for the construction of city tunnel.