In order to find the connection degree of express delivery of relevant industries from different angles. We calculate the express industry's association industry correlation weight and correlation respectively by introducing the information entropy and gray correlation analysis method. The results show that there are differences between the two kinds of methods of analyzing the same data. We further explain the sources of the differences and give the evaluation of the methods. We believed that the result of information entropy method is more convincing, we can also give our advice of the developing of domestic express industry based on the conclusion.