Abstract: The present invention relates to a long-circulating liposome modified with c(RGD-ACP-K). The present invention pertains to the field of pharmaceutical preparations, in particular to the field of targeted pharmaceutical preparations. More specifically, the present invention relates to a long-circulating liposome, the surface of the liposome being modified with c(RGD-ACP-K), and the liposome comprising doxorubicin or a pharmaceutically acceptable salt thereof such as doxorubicin hydrochloride as an anti-cancer active agent. The long-circulating liposome can targetedly deliver the anti-cancer active agent into tumor neovascular endothelial cells and tumor cells and can prolong the circulation time of the liposome in vivo, thereby enhancing the therapeutic effect of anti-tumor medicaments.