Leonardo da Vinci, a combination of science and art, was one of the greatest Italian artists from the middle of15th century to the beginning of16th century. He skillfully combined science with painting and created a masterpiece with unique artistic style. Starting with the scientific nature of Leonardo da Vinci's painting, this paper discusses his scientific research and its application in painting. In the whole history of art development, the perfect combination of science and art in the Renaissance occupies an important position in the history of the development relationship between science and art (separation-combination-re-separation). Leonardo da Vinci's works are perfect examples, and the science behind his works greatly promoted his artistic development. This function is mainly manifested in perspective, anatomy, emphasis on nature and new interpretation of imitation theory. Leonardo da Vinci was one of the painters who could skillfully use perspective skills and understand his spirit during the Renaissance. Leonardo da Vinci deepened his understanding of perspective through his own painting practice. He creatively divided perspective into three categories: line perspective, empty perspective and hidden perspective, some of which fully conform to the concept of modern perspective. Leonardo da Vinci also fully applied his own theories and experiments to his creation. His The Last Supper and The Doctor's Visit are both classic perspective works. In anatomy, Leonardo da Vinci's contribution can be divided into two parts: one is to apply anatomy to painting and promote the development of painting; The other is to use painting to record anatomical results, which has greatly promoted the development of anatomy itself.

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