The widespread use of computers brings a large number of computational tasks, leading to the increasing energy consumption. CPU undertakes the main task of computing, so it is necessary to analyze the energy consumption index to search the important factors that have influence to energy consumption. It can provide the basis for the service selection of green efficiency. This paper uses the energy consumption monitor to collect the data, constructs multiple regression models and makes univariate and multivariate correlation analysis which uses the goodness of fit to evaluate the models. Experiments show that the multivariate model can well fit the whole sample data after excluding the outliers with Mahalanobis distance.