The beauty of symmetry in mathematical aesthetics is not limited to the symmetry of objective things. As Weil said, "Symmetry is an idea. For centuries, people hope to use it to explain and create order, beauty and perfection. " Symmetry in mathematics is mainly an idea, which focuses on the rationality, symmetry and coordination of mathematical objects and even the whole mathematical system. Mathematical concepts, mathematical formulas, mathematical operations, mathematical equations, mathematical conclusions and even mathematical methods all contain wonderful symmetry. Symmetry in mathematics is the translation, symmetry or analogy of mathematics. Studying symmetry can not only broaden people's horizons, but also open up new fields. Judging from the history of mathematics development, the consideration of symmetry has promoted the development of mathematics to some extent. Such as addition, subtraction, multiplication and division. The establishment of inverse operations such as differential and integral, even Riemann integral and Lesberg integral (the division of definition domain and value domain) are the products of pursuing mathematical beauty. The growth of real number n and logarithm shows obvious asymmetry. The growth of real number is uniform, while the growth of logarithm is uneven. Mathematicians consider the symmetrical beauty of logarithm, which leads to the production of natural logarithm. For another example, in the projective plane, two points can determine a straight line, otherwise the two straight lines may not intersect. In order to eliminate this asymmetry, French mathematician Gillard Girard Desargues boldly guessed that two parallel lines intersect at an ideal point (infinity point), thus establishing the duality principle (the theorem in the projective plane is established by exchanging straight lines with points) and even projective geometry.