An ELECTRE performance evaluation model was developed to outrank the different operating conditions of air conditioning systems. Five evaluation criteria covers total energy consumption, thermal comfort PMV and PPD, indoor air quality indices such as CO2 concentration and TVOC concentration. The performance under seven different operating conditions was outranked on the TRNSYS (transient system) simulation platform. Three assignment alternatives of weight coefficients were selected to calculate the relevant credibility scores respectively. The results indicate that the proposed evaluation model can outrank the different operating conditions and select the optimum one, Moreover different weight assignments have little influence on the outranking scores. Further investigation should focus on the more evaluating criteria such as control performance and others in the comprehensive evaluation of operating conditions.