In order to understand the changes of dynamic load and the air distribution more accurately in large spaces, so as to provide a basis for air conditioning equipment selection and air conditioning and ventilation making which meet the requirements of the indicators of green building design and human body comfort, some big public buildings in Yantai were utilized to analyze the characteristics of the cooling load and the distribution of load ratio. According to the results of the analysis, we carried out selection of equipment, improving the working efficiency of air conditioning system. In addition, the distribution of air velocity and temperature were simulated by CFD, providing theory basic for the design of air conditioning and ventilation and a set of practical design methods for large public buildings.