The present invention is related to novel 20-sulfonylamidine derivatives of camptothecin (1), method of synthesizing the same, and use thereof as an antitumor agent, for examples an antitumor agent for treating nasopharyngeal, lung, breast or prostate cancer.本發明係關於一種喜樹鹼(1)的新穎20-磺基脒衍生物、其合成方法、及其作為抗腫瘤劑,例如用以治療鼻咽、肺、乳房或前列腺癌的抗腫瘤劑之用途。