Disclosed is an anti-cancer targeting conjugate modified by a multi-arm polymer, wherein modification by a water-soluble polymer can enhance the water solubility of the conjugate and increase a drug loading amount; when the targeting molecule is LRKLRKRLLLRKLRKRLL, the conjugate can increase brain targeting so as to make same pass through the blood brain barrier more easily, and can play the role of a brain-targeting peptide, allowing same to be at a higher concentration in a target tissue; and when the targeting molecule is folic acid, the conjugate can actively target tumor cells in which folate receptors are abundantly expressed, and better exert anti-tumor effects and enhance the targeting property.