By investigating the visitors flow rate of two shopping malls in Handan with the black box theory, there is the explanation of rules of personnel movement in two shopping malls, the calculation model of personnel density in shopping malls has been built via the correlative knowledge of applied mathematical statistics. Combined with the survey data of the two shopping malls, the personnel densities, the laws of personnel density distribution at different times of the day, as well as the ratio of average personnel density on working day and rest day are obtained. By calculating the air conditioning cooling load of two shopping malls in Handan and analyzing the characteristics of cooling load of two shopping malls, optimizing suggestions of air conditioning system are put forward to reduce air conditioning load according to the different cooling load characters. We suggest that the air conditioning system of two shopping malls should be optimized by improving outdoor air quality and improving the utilization rate of outdoor air.