The present invention relates to a camptothecin derivative having a structure as represented by Formula (II), in which Xn+ is selected among H+, K+, Na+, Li+, Mg2+, Ca2+, Zn2+, Fe3+, and ammonium, while R1, R2, R3, and R4 individually represent a hydrogen, a nitro group, a nitrile group, a halogen, a carboxyl group, an optionally substituted amino group, a substituted silicon group, a monocyclic aryloxy group, an optionally substituted C1-C6 alkoxy group, an optionally substituted C1-C6 alkylcarbonyl group, an optionally substituted C1-C6 alkyl group, or an optionally substituted C1-C6 cycloalkyl group； alternatively, R1 and R2 are connected via one to three other atoms to form a heterocyclic ring； and in another embodiment, R3 and R4 form a cyclic compound via -O-(CH2)n-O-, in which n = 1 or 2. The compound is provided with great aqueous solubility, compound stability, and great efficacy in treatment of cancer. [Formula (II)]
