The invention relates to a triblock polymer, a drug-loaded nano-micelle, a nano-drug as well as a preparation method and application of the nano-drug. The triblock polymer comprises a hydrophilic segment polyethylene glycol, an intermediate segment poly (methacryloyl lysine-g-(cyclodextrin polypeptide)) and a hydrophobic segment poly (aspartyl-N, N-dibutyl propylamine). The triblock polymer comprises a pH-sensitive chain segment and an MMP-2 enzyme-sensitive middle segment, and can be self-assembled into a nano-micelle; the assembled nano-micelle takes a pH-sensitive chain segment as a core, takes an MMP-2 enzyme-sensitive chain segment as a middle layer and takes methoxy polyethylene glycol as an outermost layer, so that the nano-micelle has smaller particle size, higher drug loading rate, good pH and MMP enzyme sensitivity and low toxicity to cells. The triblock polymer has the advantages that chemotherapy drugs and anti-angiogenesis drugs can be loaded at the same time, microenvironment responsive release of the drugs can be achieved, targeted drug therapy of different cells of tumor sites is achieved, and the drug carrier has great innovativeness and application value.