Mathematical model is a kind of simulation, which is an abstract and concise description of the essential attributes of practical topics with mathematical symbols, mathematical formulas, programs and graphics. It can not only explain some objective phenomena, but also predict the future development law, and also provide an optimal strategy or a better strategy in a sense for controlling the development of a phenomenon. Generally speaking, mathematical model is not a direct copy of real problems, and its establishment often requires people to observe and analyze real problems in depth and carefully, and also requires people to use all kinds of mathematical knowledge flexibly and skillfully. This process of abstracting mathematical models from practical problems with applied knowledge is called mathematical modeling.