With the development of modern statistics, both social statistics and mathematical statistics can be analyzed qualitatively and quantitatively, and the difference between them is variable and random variable. We know that the concept of "variable" was first put forward by the famous mathematician Descartes in17th century, while the concept of "random variable" was first put forward by Soviet scholars after 1930s, with a difference of three centuries. Up to Professor Wang, no second person in the world has put forward the connection, difference and mutual transformation between variables and random variables. We know that the introduction of variables has brought about the emergence and development of a series of major mathematical disciplines such as function theory, equation theory and calculus. The introduction of random variables laid the theoretical foundation of probability theory and mathematical statistics, and promoted their vigorous development. It can be seen that the concepts of variables and random variables are very valuable.