This paper selected the residential buildings in Guangxi, China, to assess energy consumption of air conditioning. Numerical analysis was carried out to evaluate design parameters that could influence the energy consumption of air conditioning. A total of 16 valid cases using an orthogonal array, L16(45 ) orthogonal experimental design (OED) were selected. OED analysis showed significant probability and, therefore, the design parameters effects on the energy consumption of air conditioning were quantitatively characterized. The conclusions were as follows: 1) the significance probability of design factors affecting the energy consumption of air conditioning ranked highest to lowest in sequence were found to be thickness of the roof, insulation material of external wall, thickness of external wall, and insulation material of the roof; 2) The simulation results of the optimal combination(A4B4C4D4) show that the cold load and the heat load are reduced by 7.63% and 17.06% respectively, and the optimization effect is significant. The results of such an evaluation can be used as an index for the planning and design process and for feedback of green building projects.