Four ancient poems belong to weeds. It is characterized by being more wild than in the past, and its overall momentum is like the Yangtze River, which is a new breakthrough in the history of cursive script development. It broke the stiff cursive style in Wei and Jin Dynasties. On the basis of the original structure, the cursive script closely connects the strokes of the upper and lower words, which is called "contact". Sometimes two words are like one word, and sometimes one word is like two words. In the arrangement of composition, the density is also very different. In writing, he also opposed the slow and steady traditional writing speed in Wei and Jin Dynasties and adopted the lyrical form of unrestrained freehand brushwork.
This cursive script is bold and unrestrained, like thunder and lightning, and suddenly Wan Li, never leaving the composition. The handwriting is ups and downs, moving and static, full of paper like a cloud, which is really the peak of cursive writing. Dong Qichang commented: "There is a cliff fall and a whirlwind rain."
Zhang Xu himself didn't pay for Four Ancient Poems, saying that Zhang Xu's works were appraised according to Dong Qichang. Later generations often say this, but it is also quite controversial.