Apparatus relates to a carbonate polymer containing a functional group of disulfide five-membered ring in the side chain and application thereof. The polymer can be prepared from cyclic carbonate monomer containing a disulfide five-membered ring functional group through the activity controllable ring-opening polymerization. For polymer, molecular weight is controlled, molecular weight distribution is narrowed and does not require the protection and deprotection procedures. Polymer prepared from the carbonate monomer through the ring-opening polymerization has biodegradability, can be used for controlling drugs release system, and can be used to prepare tumor-targeted nano-drug carrier which is sensitive to reduction and is reversible cross-linking, can support long circulation in the body, in high concentration of cancers cells can rapidly release cross-linking in the cancer cells, to release drugs, to kill cancer cells with high efficiency and specificity. Biodegradable polymer has a good application value in the tissue engineering and bio-chip coating.
