Chemotherapy is the most commonly used treatment for cancer. However, due to their short circulation time and lack of specific biological distribution, chemotherapeutic drugs cause severe systemic toxicity. Using the agents specifically binding to the targeted molecules might resolve this dilemma. Aptamers can directly connect with the drugs or couple with the nano-carrier to reduce systemic toxicity. In this review, we elucidated the definition, characteristics and screening process of aptamers. The methods of drug delivery by aptamers were illustrated in details. Furthermore, clinical application of aptamers in recent years was briefly summarized and its long-term prospects were put forward.