This paper presents the study on how interior decoration influences the energy efficiency of residential buildings during the heating period. CFD technique has been employed to study 5 typical cased under Beijing climatic condition. Experimental data has been compared with the simulation results. Comparisons of thermal performance among the 5 studied cases have been carried out to identify the key relevant factors that contribute to the declination of the energy efficiency. The paper also highlights some criteria for interior decoration design that aims to obtain best global thermal performance.