The invention discloses a class of novel camptothecin derivatives and applications in preparation of antitumor drugs. According to the present invention, the camptothecin derivative exhibits excellentin vitro biological activity in the inhibition of gastric cancer, liver cancer, breast cancer and neuroblastoma, and the mouse in vivo liver cancer bioactivity test results show that the camptothecinderivative provides good treatment effect, low toxicity and good water solubility compared to the commercial drug topotecan; and the data and analysis results prove that the prepared novel camptothecin/topotecan derivative has advantages of toxicity reducing and bioactivity improving compared to the commercial drug topotecan, such that the camptothecin derivatives as a class of the new low-toxicity and high-efficiency candidate drugs have wide application prospect.