唐代是個極為講求藝術形式法則的朝代；楷書筆法的端整嚴謹，以及書寫創作態度的理性客觀，均是其重視的藝術觀點；然而張旭的狂草也在這時綻放光彩，逞其萬般風華，對當時的大唐帝國而言，張旭的狂草，表現了另一種生命的吶喊方式，在點畫線條、墨色濃淡、飛白飄舞之中，呈具書法家的呼吸及生命霎那間的盎然狀態，表現多元的藝術情境美感。其後懷素繼之，益加光大，遂創「顛張狂素」之狂草光輝，影響後代書家甚鉅。是故，張旭狂草於書法史上，有其重要的地位。 《古詩》四帖乃張旭代表性作品，其筆勢飛動，凌空飄舞之姿，具現狂草動勢之本色。因此，本文分就其書學取徑與創作狀態、字行布白與墨色空間的安排、用筆輕重的節奏感等，所呈具之動勢美感，作一深入研究。

　　　　　In the calligraphic history of Chinese running and cursive styles, the beauty of cursive style reached the summit when Chang Hsu of Tang Dynasty created his radical cursive type. Later, Huai Su adopted his style and magnified it. Thus, there was a splendid period of radical cursive type called “mad Chang and radical Su,” which had a significant impact on the calligraphers from then on. Chang Hsu's radical cursive type played an important role in the history of Chinese calligraphy. The Four Copybooks of “Ancient Poems” were Chang Hsu's representative works. The running strokes with dancing charm fully exhibit the beauty of radical cursive type. Therefore, an in-depth investigation was made in this article to analyze the strokes, patterns, and ink shades of this great calligrapher's style.