Poly(β-amino esters) (PBAE) are used for drug carrier and have many advantages, such as pH-sensitivity, low toxicity, structural diversity and the synthetic method of PBAE is easy. Therefore they are possessed broad application prospect in tumor-targeted drugs delivery systems. In this paper, the structural features and target drugs delivery property of PBAE are reviewed. The application forms of PBAE and different anti-cancer drugs loaded in the copolymer for tumor-targeted drugs delivery systems are introduced particularly.