A multi-branched drug conjugate of formula (I) or a pharmaceutically acceptable salt thereof. In the formula, R is an organic center, POLY is a polymer, L is a multivalent linker, T is a targeting molecule, D is an active agent, and q is any integer between 3 and 8. The symbol “*” in L represents a junction point of the multivalent linker L and the targeting molecule T, “#” represents a junction point of the multivalent linker L and the active agent D, and “%” represents a junction point of the multivalent linker L and POLY. 1 is any integer between 2 and 20, and m and n are each an integer between 0 and 10. T is iRGD, cRGD, tLyp-1, Lyp-1, RPARPAR, Angiopep2, or GE11. D is a camptothecin drug.