Four-character poetry is a genre of ancient Chinese poetry. "Four-character poem" refers to a poem composed of four words. Four-character poem refers to a poem written in four sentences, which runs through the capital. This is reflected in the ancient songs and rhymes of Zhouyi. Although there are three, five, seven, eight and nine-character sentences in the Book of Songs, the first collection of Chinese poems in China, they are basically four-character sentences.