Du Fu's middle-aged poems are called "the history of poetry" because of his gloomy poetic style and feelings of worrying about the country and the people. His poems are good at antique and rhythmic poems, and have various styles. He accurately summed up his work style with the words "depressed and frustrated", mainly focusing on depression. Du Fu lived in the historical period from prosperity to decline in the Tang Dynasty. Most of his poems involve social unrest, political darkness and people's sufferings. His poems reflected the social contradictions and people's sufferings at that time. His poems recorded the historical changes of the Tang Dynasty from prosperity to decline, and expressed the lofty Confucian spirit of benevolence and strong sense of hardship, so they were called "the history of poetry". Du Fu is concerned about the country and the people, with noble personality and exquisite poetic skills. Du Fu wrote more than 1500 poems in his life, many of which are famous works that have been celebrated through the ages, such as Three Officials and Three Farewells. Among them, the "three officials" are Shi Haoguan, Xin 'an official and Tongguan official, and the "three farewell" are newly married, homeless and resigned. Du Fu's poems handed down from generation to generation are the most extensive in the Tang Dynasty, and he is one of the most outstanding poets in the Tang Dynasty, which has a far-reaching influence on later generations. Du Fu's works are known as the scars of the world and the sages in poetry. The people are in poverty, and the bottom of the pen is turbulent. It is a masterpiece of realistic poetry.