Mathematical modeling is a process of describing actual phenomena with mathematical language. The actual phenomena here include not only concrete natural phenomena such as free fall, but also abstract phenomena such as customers' value preference for a certain commodity. The description here includes not only the description of external form and internal mechanism, but also the prediction, experiment and explanation of actual phenomena. We can also intuitively understand this concept: mathematical modeling is the process of turning a pure mathematician (a mathematician who only knows mathematics but doesn't know its application in practice) into a physicist.