The formal beauty rules of plane composition are as follows: \n1. Change and unity: Change and unity are the basic formal principles in the field of art, and are also the general rules of formal beauty in plane composition. It refers to the law of the combination of various formal elements in formal beauty according to a changing and regular structure, which embodies the law of the unity of opposites among various factors in life and nature. \n2. Symmetry and balance: Symmetry and balance are also manifestations of change and unity. Usually symmetry is more likely to create a sense of unity, while balance emphasizes the dynamics and changes in the picture. In design, balance is a relatively free form of expression. It is visually more flexible and fresh than symmetry, with a sense of movement, and full of change and unified formal beauty. \n3. Contrast and harmony: Contrast and harmony are also commonly used principles in art. Contrast is to make obvious differences between different elements of the picture, creating a sense of contradiction, thereby emphasizing their respective characteristics. Harmony is a coordinated relationship between different elements of the picture, giving the picture a sense of unity. \n4. Proportion and scale: Proportion and scale are one of the formal beauty rules of plane composition. It refers to making the picture more coordinated and beautiful by determining the proportional relationship between different elements. \n5. Rhythm and rhythm: Rhythm and rhythm is a musical concept that is widely used in the field of design. Rhythm refers to the repeated arrangement of elements in the picture according to certain rules, forming a sense of rhythm. Rhythm refers to the arrangement of elements in the picture according to certain rules, forming a sense of melody. \n6. Unity and diversity: Unity and diversity are one of the formal beauty rules of plane composition. It refers to organically combining different elements in the picture through unified themes, styles, colors and other elements to form a sense of unity. At the same time, on the basis of unity, diverse elements can also be appropriately introduced to make the picture richer and more interesting. \nThese formal beauty principles are not isolated. They can be integrated with each other to form a perfect design. In practical applications, these rules need to be flexibly used according to specific themes and requirements to create works that meet aesthetic needs.