Han Li is the official script in the mature stage from the middle and late Western Han Dynasty to the Eastern Han Dynasty. During this period, the development of official script gradually became complete and its structure was fixed. In the early Eastern Han Dynasty, the reform of official script had begun to take shape. The structure of the fonts was more simplified, the shape gradually developed into a flat square, the square folding brushwork became more obvious, and the round and even characteristics of seal script basically disappeared. During the period of Emperor Huan of the Han Dynasty, Emperor Han Ling of the Han Dynasty and Emperor Xian of the Han Dynasty, Han Li reached its heyday and became the standard font commonly used in society. During this period, official script had completely gotten rid of the influence of seal script. Its structure showed flat features, the fonts were regular and delicate, and they were stable and stretched horizontally. In terms of form, it forms a unique shape of "silkworm head and swallow tail", which has the agility of a swallow flying, but it is also graceful and generous, vigorous and straight, full of interest; in terms of brushwork, it is mainly square strokes, with round strokes, and is rebellious. The flat surface combines the virtual and the real, and the ripples are highlighted; in terms of the overall style, it is compact up and down, stretched left and right, sophisticated and clever in simplicity, beautiful and interesting in quaintness, rigorous yet lively, regular yet natural in change; in terms of composition, The vertical and horizontal lines are clear, the density is even, and it is regular. In short, the emergence and development of official script not only plays an important role in the history of calligraphy, but also creates a new situation in the history of Chinese character development.