This article mentioned the psychological basis for the formation of mathematical symbols for preschoolers. The result indicated that psychology was the basis for the formation of mathematical symbols for preschoolers such as quantity, number, numeration, space, time, shape, and size. However, at each age of preschool, the content, form, and method of formation were different with various requirements based on the physiological development of children and suitability with developmental characteristics of each child. It also proved that the appropriate impact orientation such as interdisciplinary integration in preschool education will enhance effectiveness for caring and educating children.